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1.
Commun Biol ; 7(1): 345, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38509283

RESUMO

The scaffolding A-kinase anchoring protein 150 (AKAP150) is critically involved in kinase and phosphatase regulation of synaptic transmission/plasticity, and neuronal excitability. Emerging evidence also suggests that AKAP150 signaling may play a key role in brain's processing of rewarding/aversive experiences, however its role in the lateral habenula (LHb, as an important brain reward circuitry) is completely unknown. Using whole cell patch clamp recordings in LHb of male wildtype and ΔPKA knockin mice (with deficiency in AKAP-anchoring of PKA), here we show that the genetic disruption of PKA anchoring to AKAP150 significantly reduces AMPA receptor-mediated glutamatergic transmission and prevents the induction of presynaptic endocannabinoid-mediated long-term depression in LHb neurons. Moreover, ΔPKA mutation potentiates GABAA receptor-mediated inhibitory transmission while increasing LHb intrinsic excitability through suppression of medium afterhyperpolarizations. ΔPKA mutation-induced suppression of medium afterhyperpolarizations also blunts the synaptic and neuroexcitatory actions of the stress neuromodulator, corticotropin releasing factor (CRF), in mouse LHb. Altogether, our data suggest that AKAP150 complex signaling plays a critical role in regulation of AMPA and GABAA receptor synaptic strength, glutamatergic plasticity and CRF neuromodulation possibly through AMPA receptor and potassium channel trafficking and endocannabinoid signaling within the LHb.


Assuntos
Hormônio Liberador da Corticotropina , Habenula , Animais , Masculino , Camundongos , Proteínas de Ancoragem à Quinase A/genética , Proteínas de Ancoragem à Quinase A/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Endocanabinoides , Habenula/metabolismo , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Receptores de AMPA/genética , Receptores de AMPA/metabolismo , Receptores de GABA-A/metabolismo , Transmissão Sináptica/fisiologia
2.
Elife ; 122023 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-37490324

RESUMO

Pathological loss-of-function mutations in cyclin-dependent kinase-like 5 (CDKL5) cause CDKL5 deficiency disorder (CDD), a rare and severe neurodevelopmental disorder associated with severe and medically refractory early-life epilepsy, motor, cognitive, visual, and autonomic disturbances in the absence of any structural brain pathology. Analysis of genetic variants in CDD has indicated that CDKL5 kinase function is central to disease pathology. CDKL5 encodes a serine-threonine kinase with significant homology to GSK3ß, which has also been linked to synaptic function. Further, Cdkl5 knock-out rodents have increased GSK3ß activity and often increased long-term potentiation (LTP). Thus, development of a specific CDKL5 inhibitor must be careful to exclude cross-talk with GSK3ß activity. We synthesized and characterized specific, high-affinity inhibitors of CDKL5 that do not have detectable activity for GSK3ß. These compounds are very soluble in water but blood-brain barrier penetration is low. In rat hippocampal brain slices, acute inhibition of CDKL5 selectively reduces postsynaptic function of AMPA-type glutamate receptors in a dose-dependent manner. Acute inhibition of CDKL5 reduces hippocampal LTP. These studies provide new tools and insights into the role of CDKL5 as a newly appreciated key kinase necessary for synaptic plasticity. Comparisons to rodent knock-out studies suggest that compensatory changes have limited the understanding of the roles of CDKL5 in synaptic physiology, plasticity, and human neuropathology.


Assuntos
Hipocampo , Proteínas Serina-Treonina Quinases , Animais , Camundongos , Humanos , Glicogênio Sintase Quinase 3 beta/genética , Camundongos Knockout , Proteínas Serina-Treonina Quinases/metabolismo , Hipocampo/metabolismo , Quinases Ciclina-Dependentes
3.
bioRxiv ; 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37162893

RESUMO

Pathological loss-of-function mutations in cyclin-dependent kinase-like 5 ( CDKL5 ) cause CDKL5 deficiency disorder (CDD), a rare and severe neurodevelopmental disorder associated with severe and medically refractory early-life epilepsy, motor, cognitive, visual and autonomic disturbances in the absence of any structural brain pathology. Analysis of genetic variants in CDD have indicated that CDKL5 kinase function is central to disease pathology. CDKL5 encodes a serine-threonine kinase with significant homology to GSK3b, which has also been linked to synaptic function. Further, Cdkl5 knock-out rodents have increased GSK3b activity and often increased long-term potentiation (LTP). Thus, development of a specific CDKL5 inhibitor must be careful to exclude cross-talk with GSK3b activity. We synthesized and characterized specific, high-affinity inhibitors of CDKL5 that do not have detectable activity for GSK3b. These compounds are very soluble in water but blood-brain barrier penetration is low. In rat hippocampal brain slices, acute inhibition of CDKL5 selectively reduces post-synaptic function of AMPA-type glutamate receptors in a dose-dependent manner. Acute inhibition of CDKL5 reduces hippocampal LTP. These studies provide new tools and insights into the role of CDKL5 as a newly appreciated, key kinase necessary for synaptic plasticity. Comparisons to rodent knock-out studies suggest that compensatory changes have limited the understanding of the roles of CDKL5 in synaptic physiology, plasticity and human neuropathology.

4.
Neuropharmacology ; 220: 109271, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36162529

RESUMO

Genetic alterations in autism spectrum disorders (ASD) frequently disrupt balance between synaptic excitation and inhibition and alter plasticity in the hippocampal CA1 region. Individuals with Timothy Syndrome (TS), a genetic disorder caused by CaV1.2 L-type Ca2+ channel (LTCC) gain-of function mutations, such as G406R, exhibit social deficits, repetitive behaviors, and cognitive impairments characteristic of ASD that are phenocopied in TS2-neo mice expressing G406R. Here, we characterized hippocampal CA1 synaptic function in male TS2-neo mice and found basal excitatory transmission was slightly increased and inhibitory transmission strongly decreased. We also found distinct impacts on two LTCC-dependent forms of long-term potentiation (LTP) synaptic plasticity that were not readily consistent with LTCC gain-of-function. LTP induced by high-frequency stimulation (HFS) was strongly impaired in TS2-neo mice, suggesting decreased LTCC function. Yet, CaV1.2 expression, basal phosphorylation, and current density were similar for WT and TS2-neo. However, this HFS-LTP also required GABAA receptor activity, and thus may be impaired in TS2-neo due to decreased inhibitory transmission. In contrast, LTP induced in WT mice by prolonged theta-train (PTT) stimulation in the presence of a ß-adrenergic receptor agonist to increase CaV1.2 phosphorylation was partially induced in TS2-neo mice by PTT stimulation alone, consistent with increased LTCC function. Overall, our findings provide insights regarding how altered CaV1.2 channel function disrupts basal transmission and plasticity that could be relevant for neurobehavioral alterations in ASD.


Assuntos
Canais de Cálcio Tipo L , Potenciação de Longa Duração , Receptores de GABA-A , Animais , Transtorno Autístico , Região CA1 Hipocampal , Canais de Cálcio Tipo L/genética , Modelos Animais de Doenças , Hipocampo/metabolismo , Síndrome do QT Longo , Masculino , Camundongos , Mutação , Receptores de GABA-A/metabolismo , Sinapses/metabolismo , Sindactilia
5.
Cell Rep ; 37(1): 109786, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34610314

RESUMO

Regulated insertion and removal of postsynaptic AMPA glutamate receptors (AMPARs) mediates hippocampal long-term potentiation (LTP) and long-term depression (LTD) synaptic plasticity underlying learning and memory. In Alzheimer's disease ß-amyloid (Aß) oligomers may impair learning and memory by altering AMPAR trafficking and LTP/LTD balance. Importantly, Ca2+-permeable AMPARs (CP-AMPARs) assembled from GluA1 subunits are excluded from hippocampal synapses basally but can be recruited rapidly during LTP and LTD to modify synaptic strength and signaling. By employing mouse knockin mutations that disrupt anchoring of the kinase PKA or phosphatase Calcineurin (CaN) to the postsynaptic scaffold protein AKAP150, we find that local AKAP-PKA signaling is required for CP-AMPAR recruitment, which can facilitate LTP but also, paradoxically, prime synapses for Aß impairment of LTP mediated by local AKAP-CaN LTD signaling that promotes subsequent CP-AMPAR removal. These findings highlight the importance of PKA/CaN signaling balance and CP-AMPARs in normal plasticity and aberrant plasticity linked to disease.


Assuntos
Proteínas de Ancoragem à Quinase A/genética , Peptídeos beta-Amiloides/farmacologia , Calcineurina/genética , Proteínas Quinases Dependentes de AMP Cíclico/genética , Potenciação de Longa Duração/efeitos dos fármacos , Depressão Sináptica de Longo Prazo/efeitos dos fármacos , Receptores de AMPA/metabolismo , Proteínas de Ancoragem à Quinase A/metabolismo , Animais , Região CA1 Hipocampal/metabolismo , Calcineurina/metabolismo , Cálcio/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Depressão Sináptica de Longo Prazo/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de AMPA/antagonistas & inibidores , Receptores de Glutamato/química , Receptores de Glutamato/metabolismo , Transdução de Sinais/efeitos dos fármacos , Espermina/análogos & derivados , Espermina/farmacologia , Sinapses/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
6.
Ecol Lett ; 24(9): 1966-1975, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34176203

RESUMO

Personality traits, such as the propensity to cooperate, are often inherited from parents to offspring, but the pathway of inheritance is unclear. Traits could be inherited via genetic or parental effects, or culturally via social learning from role models. However, these pathways are difficult to disentangle in natural systems as parents are usually the source of all of these effects. Here, we exploit natural 'cross fostering' in wild banded mongooses to investigate the inheritance of cooperative behaviour. Our analysis of 800 adult helpers over 21 years showed low but significant genetic heritability of cooperative personalities in males but not females. Cross fostering revealed little evidence of cultural heritability: offspring reared by particularly cooperative helpers did not become more cooperative themselves. Our results demonstrate that cooperative personalities are not always highly heritable in wild, and that the basis of behavioural traits can vary within a species (here, by sex).


Assuntos
Herpestidae , Animais , Comportamento Cooperativo , Herpestidae/genética , Masculino , Linhagem , Personalidade , Fenótipo
7.
Cell Rep ; 31(12): 107785, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32579917

RESUMO

Molecular mechanisms underlying plasticity at brain inhibitory synapses remain poorly characterized. Increased postsynaptic clustering of GABAA receptors (GABAARs) rapidly strengthens inhibition during inhibitory long-term potentiation (iLTP). However, it is unclear how synaptic GABAAR clustering is maintained to sustain iLTP. Here, we identify a role for miR376c in regulating the translation of mRNAs encoding the synaptic α1 and γ2 GABAAR subunits, GABRA1 and GABRG2, respectively. Following iLTP induction, transcriptional repression of miR376c is induced through a calcineurin-NFAT-HDAC signaling pathway and promotes increased translation and clustering of synaptic GABAARs. This pathway is essential for the long-term expression of iLTP and is blocked by miR376c overexpression, specifically impairing inhibitory synaptic strength. Finally, we show that local de novo synthesis of synaptic GABAARs occurs exclusively in dendrites and in a miR376c-dependent manner following iLTP. Together, this work describes a local post-transcriptional mechanism that regulates inhibitory synaptic plasticity via miRNA control of dendritic protein synthesis.


Assuntos
Potenciação de Longa Duração/genética , MicroRNAs/genética , Biossíntese de Proteínas/genética , Receptores de GABA-A/genética , Animais , Sequência de Bases , Calcineurina/metabolismo , Dendritos/metabolismo , Regulação da Expressão Gênica , Inativação Gênica , Células HEK293 , Humanos , MicroRNAs/metabolismo , Fatores de Transcrição NFATC/metabolismo , Inibição Neural , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Receptores de GABA-A/metabolismo , Sinapses/metabolismo , Transcrição Gênica
8.
J Neurosci ; 38(11): 2863-2876, 2018 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-29440558

RESUMO

Neuronal information processing requires multiple forms of synaptic plasticity mediated by NMDARs and AMPA-type glutamate receptors (AMPARs). These plasticity mechanisms include long-term potentiation (LTP) and long-term depression (LTD), which are Hebbian, homosynaptic mechanisms locally regulating synaptic strength of specific inputs, and homeostatic synaptic scaling, which is a heterosynaptic mechanism globally regulating synaptic strength across all inputs. In many cases, LTP and homeostatic scaling regulate AMPAR subunit composition to increase synaptic strength via incorporation of Ca2+-permeable receptors (CP-AMPAR) containing GluA1, but lacking GluA2, subunits. Previous work by our group and others demonstrated that anchoring of the kinase PKA and the phosphatase calcineurin (CaN) to A-kinase anchoring protein (AKAP) 150 play opposing roles in regulation of GluA1 Ser845 phosphorylation and CP-AMPAR synaptic incorporation during hippocampal LTP and LTD. Here, using both male and female knock-in mice that are deficient in PKA or CaN anchoring, we show that AKAP150-anchored PKA and CaN also play novel roles in controlling CP-AMPAR synaptic incorporation during homeostatic plasticity in hippocampal neurons. We found that genetic disruption of AKAP-PKA anchoring prevented increases in Ser845 phosphorylation and CP-AMPAR synaptic recruitment during rapid homeostatic synaptic scaling-up induced by combined blockade of action potential firing and NMDAR activity. In contrast, genetic disruption of AKAP-CaN anchoring resulted in basal increases in Ser845 phosphorylation and CP-AMPAR synaptic activity that blocked subsequent scaling-up by preventing additional CP-AMPAR recruitment. Thus, the balanced, opposing phospho-regulation provided by AKAP-anchored PKA and CaN is essential for control of both Hebbian and homeostatic plasticity mechanisms that require CP-AMPARs.SIGNIFICANCE STATEMENT Neuronal circuit function is shaped by multiple forms of activity-dependent plasticity that control excitatory synaptic strength, including LTP/LTD that adjusts strength of individual synapses and homeostatic plasticity that adjusts overall strength of all synapses. Mechanisms controlling LTP/LTD and homeostatic plasticity were originally thought to be distinct; however, recent studies suggest that CP-AMPAR phosphorylation regulation is important during both LTP/LTD and homeostatic plasticity. Here we show that CP-AMPAR regulation by the kinase PKA and phosphatase CaN coanchored to the scaffold protein AKAP150, a mechanism previously implicated in LTP/LTD, is also crucial for controlling synaptic strength during homeostatic plasticity. These novel findings significantly expand our understanding of homeostatic plasticity mechanisms and further emphasize how intertwined they are with LTP and LTD.


Assuntos
Proteínas de Ancoragem à Quinase A/genética , Proteínas de Ancoragem à Quinase A/fisiologia , Homeostase/genética , Homeostase/fisiologia , Plasticidade Neuronal/genética , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/fisiologia , Receptores de AMPA/genética , Receptores de AMPA/fisiologia , Sinapses/fisiologia , Potenciais de Ação/genética , Potenciais de Ação/fisiologia , Animais , Fenômenos Eletrofisiológicos/fisiologia , Potenciais Pós-Sinápticos Excitadores/genética , Potenciais Pós-Sinápticos Excitadores/fisiologia , Feminino , Técnicas de Introdução de Genes , Potenciação de Longa Duração/genética , Potenciação de Longa Duração/fisiologia , Masculino , Camundongos , Plasticidade Neuronal/fisiologia , Cultura Primária de Células , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/fisiologia , Recrutamento Neurofisiológico/genética , Recrutamento Neurofisiológico/fisiologia
9.
PLoS One ; 13(1): e0190740, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29315317

RESUMO

Studying ecological and evolutionary processes in the natural world often requires research projects to follow multiple individuals in the wild over many years. These projects have provided significant advances but may also be hampered by needing to accurately and efficiently collect and store multiple streams of the data from multiple individuals concurrently. The increase in the availability and sophistication of portable computers (smartphones and tablets) and the applications that run on them has the potential to address many of these data collection and storage issues. In this paper we describe the challenges faced by one such long-term, individual-based research project: the Banded Mongoose Research Project in Uganda. We describe a system we have developed called Mongoose 2000 that utilises the potential of apps and portable computers to meet these challenges. We discuss the benefits and limitations of employing such a system in a long-term research project. The app and source code for the Mongoose 2000 system are freely available and we detail how it might be used to aid data collection and storage in other long-term individual-based projects.


Assuntos
Evolução Biológica , Ecossistema , Monitoramento Ambiental/métodos , Animais , Computadores , Coleta de Dados , Bases de Dados Factuais , Feminino , Herpestidae , Humanos , Masculino , Gravidez , Smartphone , Uganda
10.
Proc Natl Acad Sci U S A ; 114(20): 5207-5212, 2017 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-28439031

RESUMO

Kin selection theory predicts that, where kin discrimination is possible, animals should typically act more favorably toward closer genetic relatives and direct aggression toward less closely related individuals. Contrary to this prediction, we present data from an 18-y study of wild banded mongooses, Mungos mungo, showing that females that are more closely related to dominant individuals are specifically targeted for forcible eviction from the group, often suffering severe injury, and sometimes death, as a result. This pattern cannot be explained by inbreeding avoidance or as a response to more intense local competition among kin. Instead, we use game theory to show that such negative kin discrimination can be explained by selection for unrelated targets to invest more effort in resisting eviction. Consistent with our model, negative kin discrimination is restricted to eviction attempts of older females capable of resistance; dominants exhibit no kin discrimination when attempting to evict younger females, nor do they discriminate between more closely or less closely related young when carrying out infanticidal attacks on vulnerable infants who cannot defend themselves. We suggest that in contexts where recipients of selfish acts are capable of resistance, the usual prediction of positive kin discrimination can be reversed. Kin selection theory, as an explanation for social behavior, can benefit from much greater exploration of sequential social interactions.


Assuntos
Conflito Psicológico , Comportamento Cooperativo , Família/psicologia , Herpestidae/psicologia , Agressão/psicologia , Animais , Comportamento Animal , Dominação-Subordinação , Feminino , Teoria dos Jogos , Endogamia , Masculino , Reprodução , Comportamento Social
11.
Ecol Evol ; 7(6): 1712-1724, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28331582

RESUMO

Early-life ecological conditions have major effects on survival and reproduction. Numerous studies in wild systems show fitness benefits of good quality early-life ecological conditions ("silver-spoon" effects). Recently, however, some studies have reported that poor-quality early-life ecological conditions are associated with later-life fitness advantages and that the effect of early-life conditions can be sex-specific. Furthermore, few studies have investigated the effect of the variability of early-life ecological conditions on later-life fitness. Here, we test how the mean and variability of early-life ecological conditions affect the longevity and reproduction of males and females using 14 years of data on wild banded mongooses (Mungos mungo). Males that experienced highly variable ecological conditions during development lived longer and had greater lifetime fitness, while those that experienced poor early-life conditions lived longer but at a cost of reduced fertility. In females, there were no such effects. Our study suggests that exposure to more variable environments in early life can result in lifetime fitness benefits, whereas differences in the mean early-life conditions experienced mediate a life-history trade-off between survival and reproduction. It also demonstrates how early-life ecological conditions can produce different selection pressures on males and females.

12.
Behav Ecol ; 27(4): 978-987, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27418750

RESUMO

Ecological conditions are expected to have an important influence on individuals' investment in cooperative care. However, the nature of their effects is unclear: both favorable and unfavorable conditions have been found to promote helping behavior. Recent studies provide a possible explanation for these conflicting results by suggesting that increased ecological variability, rather than changes in mean conditions, promote cooperative care. However, no study has tested whether increased ecological variability promotes individual-level helping behavior or the mechanisms involved. We test this hypothesis in a long-term study population of the cooperatively breeding banded mongoose, Mungos mungo, using 14 years of behavioral and meteorological data to explore how the mean and variability of ecological conditions influence individual behavior, body condition, and survival. Female body condition was more sensitive to changes in rainfall leading to poorer female survival and pronounced male-biased group compositions after periods of high rainfall variability. After such periods, older males invested more in helping behavior, potentially because they had fewer mating opportunities. These results provide the first empirical evidence for increased individual helping effort in more variable ecological conditions and suggest this arises because of individual differences in the effect of ecological conditions on body condition and survival, and the knock-on effect on social group composition. Individual differences in sensitivity to environmental variability, and the impacts this has on the internal structure and composition of animal groups, can exert a strong influence on the evolution and maintenance of social behaviors, such as cooperative care.

13.
Neuron ; 89(5): 1000-15, 2016 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-26938443

RESUMO

Information processing in the brain requires multiple forms of synaptic plasticity that converge on regulation of NMDA and AMPA-type glutamate receptors (NMDAR, AMPAR), including long-term potentiation (LTP) and long-term depression (LTD) and homeostatic scaling. In some cases, LTP and homeostatic plasticity regulate synaptic AMPAR subunit composition to increase the contribution of Ca(2+)-permeable receptors (CP-AMPARs) containing GluA1 but lacking GluA2 subunits. Here, we show that PKA anchored to the scaffold protein AKAP150 regulates GluA1 phosphorylation and plays a novel role controlling CP-AMPAR synaptic incorporation during NMDAR-dependent LTD. Using knockin mice that are deficient in AKAP-anchoring of either PKA or the opposing phosphatase calcineurin, we found that CP-AMPARs are recruited to hippocampal synapses by anchored PKA during LTD induction but are then rapidly removed by anchored calcineurin. Importantly, blocking CP-AMPAR recruitment, removal, or activity interferes with LTD. Thus, CP-AMPAR synaptic recruitment is required to transiently augment NMDAR Ca(2+) signaling during LTD induction.


Assuntos
Proteínas de Ancoragem à Quinase A/metabolismo , Calcineurina/metabolismo , Cálcio/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Depressão Sináptica de Longo Prazo/fisiologia , Receptores de AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/fisiologia , Proteínas de Ancoragem à Quinase A/genética , Animais , Calcineurina/genética , Proteínas Quinases Dependentes de AMP Cíclico/genética , Estimulação Elétrica , Inibidores Enzimáticos/farmacologia , Fármacos Atuantes sobre Aminoácidos Excitatórios/farmacologia , Hipocampo/citologia , Hipocampo/ultraestrutura , Depressão Sináptica de Longo Prazo/efeitos dos fármacos , Depressão Sináptica de Longo Prazo/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Moleculares , Mutação/genética , Receptores de AMPA/genética , Receptores de N-Metil-D-Aspartato/genética , Coloração pela Prata , Sinapses/genética , Sinapses/ultraestrutura , Potenciais Sinápticos/efeitos dos fármacos , Potenciais Sinápticos/genética
14.
Proc Biol Sci ; 283(1826): 20152607, 2016 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-26936245

RESUMO

In many vertebrate societies, forced eviction of group members is an important determinant of population structure, but little is known about what triggers eviction. Three main explanations are: (i) the reproductive competition hypothesis, (ii) the coercion of cooperation hypothesis, and (iii) the adaptive forced dispersal hypothesis. The last hypothesis proposes that dominant individuals use eviction as an adaptive strategy to propagate copies of their alleles through a highly structured population. We tested these hypotheses as explanations for eviction in cooperatively breeding banded mongooses (Mungos mungo), using a 16-year dataset on life history, behaviour and relatedness. In this species, groups of females, or mixed-sex groups, are periodically evicted en masse. Our evidence suggests that reproductive competition is the main ultimate trigger for eviction for both sexes. We find little evidence that mass eviction is used to coerce helping, or as a mechanism to force dispersal of relatives into the population. Eviction of females changes the landscape of reproductive competition for remaining males, which may explain why males are evicted alongside females. Our results show that the consequences of resolving within-group conflict resonate through groups and populations to affect population structure, with important implications for social evolution.


Assuntos
Herpestidae/fisiologia , Reprodução , Comportamento Social , Animais , Feminino , Masculino , Uganda
15.
Sci Rep ; 6: 20013, 2016 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-26817515

RESUMO

Female intrasexual competition is intense in cooperatively breeding species where offspring compete locally for resources and helpers. In mammals, females have been proposed to adjust prenatal investment according to the intensity of competition in the postnatal environment (a form of 'predictive adaptive response'; PAR). We carried out a test of this hypothesis using ultrasound scanning of wild female banded mongooses in Uganda. In this species multiple females give birth together to a communal litter, and all females breed regularly from one year old. Total prenatal investment (size times the number of fetuses) increased with the number of potential female breeders in the group. This relationship was driven by fetus size rather than number. The response to competition was particularly strong in low weight females and when ecological conditions were poor. Increased prenatal investment did not trade off against maternal survival. In fact we found the opposite relationship: females with greater levels of prenatal investment had elevated postnatal maternal survival. Our results support the hypothesis that mammalian prenatal development is responsive to the intensity of postnatal competition. Understanding whether these responses are adaptive requires information on the long-term consequences of prenatal investment for offspring fitness.


Assuntos
Comportamento Competitivo , Herpestidae , Reprodução , Comportamento Sexual Animal , Animais , Cruzamento , Feminino , Uganda
16.
Behav Ecol ; 26(6): 1486-1494, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26609201

RESUMO

Females of many animal species seek mating opportunities with multiple males, despite being able to obtain sufficient sperm to father their offspring from a single male. In animals that live in stable social groups, females often choose to mate outside their group resulting in extra-group paternity (EGP). One reason proposed to explain female choice for extra-group males is to obtain compatible genes, for example, in order to avoid inbreeding depression in offspring. The benefits of such extra-group paternities could be substantial if they result in fitter, outbred offspring. However, avoiding inbreeding in this way could be costly for females, for example, through retaliation by cuckolded males or through receiving aggression while prospecting for extra-group mating opportunities. We investigate the costs and benefits of EGP in the banded mongoose Mungos mungo, a cooperatively breeding mammal in which within-group mates are sometimes close relatives. We find that pups born to females that mate with extra-group males are more genetically heterozygous are heavier and are more likely to survive to independence than pups born to females that mate within their group. However, extra-group matings also involve substantial costs as they occur during violent encounters that sometimes result in injury and death. This appears to lead femalebanded mongooses to adaptively adjust EGP levels according to the current risk of inbreeding associated with mating within the group. For group-living animals, the costs of intergroup interactions may help to explain variation in both inbreeding rates and EGP within and between species.

17.
Mol Ecol ; 24(14): 3738-51, 2015 07.
Artigo em Inglês | MEDLINE | ID: mdl-26095171

RESUMO

Inbreeding and inbreeding avoidance are key factors in the evolution of animal societies, influencing dispersal and reproductive strategies which can affect relatedness structure and helping behaviours. In cooperative breeding systems, individuals typically avoid inbreeding through reproductive restraint and/or dispersing to breed outside their natal group. However, where groups contain multiple potential mates of varying relatedness, strategies of kin recognition and mate choice may be favoured. Here, we investigate male mate choice and female control of paternity in the banded mongoose (Mungos mungo), a cooperatively breeding mammal where both sexes are often philopatric and mating between relatives is known to occur. We find evidence suggestive of inbreeding depression in banded mongooses, indicating a benefit to avoiding breeding with relatives. Successfully breeding pairs were less related than expected under random mating, which appeared to be driven by both male choice and female control of paternity. Male banded mongooses actively guard females to gain access to mating opportunities, and this guarding behaviour is preferentially directed towards less closely related females. Guard-female relatedness did not affect the guard's probability of gaining reproductive success. However, where mate-guards are unsuccessful, they lose paternity to males that are less related to the females than themselves. Together, our results suggest that both sexes of banded mongoose use kin discrimination to avoid inbreeding. Although this strategy appears to be rare among cooperative breeders, it may be more prominent in species where relatedness to potential mates is variable, and/or where opportunities for dispersal and mating outside of the group are limited.


Assuntos
Herpestidae/genética , Endogamia , Preferência de Acasalamento Animal , Animais , Teorema de Bayes , Feminino , Aptidão Genética , Genótipo , Herpestidae/fisiologia , Masculino , Repetições de Microssatélites , Modelos Genéticos , Dados de Sequência Molecular , Análise de Sequência de DNA
18.
J Neurosci ; 35(2): 442-56, 2015 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-25589740

RESUMO

Phosphorylation and dephosphorylation of AMPA-type ionotropic glutamate receptors (AMPARs) by kinases and phosphatases and interactions with scaffold proteins play essential roles in regulating channel biophysical properties and trafficking events that control synaptic strength during NMDA receptor-dependent synaptic plasticity, such as LTP and LTD. We previously demonstrated that palmitoylation of the AMPAR-linked scaffold protein A-kinase anchoring protein (AKAP) 79/150 is required for its targeting to recycling endosomes in dendrites, where it regulates exocytosis from these compartments that is required for LTP-stimulated enlargement of postsynaptic dendritic spines, delivery of AMPARs to the plasma membrane, and maintenance of synaptic potentiation. Here, we report that the recycling endosome-resident palmitoyl acyltransferase DHHC2 interacts with and palmitoylates AKAP79/150 to regulate these plasticity signaling mechanisms. In particular, RNAi-mediated knockdown of DHHC2 expression in rat hippocampal neurons disrupted stimulation of exocytosis from recycling endosomes, enlargement of dendritic spines, AKAP recruitment to spines, and potentiation of AMPAR-mediated synaptic currents that occur during LTP. Importantly, expression of a palmitoylation-independent lipidated AKAP mutant in DHHC2-deficient neurons largely restored normal plasticity regulation. Thus, we conclude that DHHC2-AKAP79/150 signaling is an essential regulator of dendritic recycling endosome exocytosis that controls both structural and functional plasticity at excitatory synapses.


Assuntos
Proteínas de Ancoragem à Quinase A/metabolismo , Aciltransferases/metabolismo , Endossomos/metabolismo , Exocitose , Potenciação de Longa Duração , Aciltransferases/genética , Animais , Células COS , Células Cultivadas , Chlorocebus aethiops , Espinhas Dendríticas/metabolismo , Feminino , Células HEK293 , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Lipoilação , Masculino , Ratos , Ratos Sprague-Dawley , Sinapses/metabolismo , Sinapses/fisiologia
19.
Cell Rep ; 7(5): 1577-1588, 2014 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-24835999

RESUMO

L-type voltage-gated Ca2+ channels (LTCC) couple neuronal excitation to gene transcription. LTCC activity is elevated by the cyclic AMP (cAMP)-dependent protein kinase (PKA) and depressed by the Ca2+-dependent phosphatase calcineurin (CaN), and both enzymes are localized to the channel by A-kinase anchoring protein 79/150 (AKAP79/150). AKAP79/150 anchoring of CaN also promotes LTCC activation of transcription through dephosphorylation of the nuclear factor of activated T cells (NFAT). We report here that the basal activity of AKAP79/150-anchored PKA maintains neuronal LTCC coupling to CaN-NFAT signaling by preserving LTCC phosphorylation in opposition to anchored CaN. Genetic disruption of AKAP-PKA anchoring promoted redistribution of the kinase out of postsynaptic dendritic spines, profound decreases in LTCC phosphorylation and Ca2+ influx, and impaired NFAT movement to the nucleus and activation of transcription. Thus, LTCC-NFAT transcriptional signaling in neurons requires precise organization and balancing of PKA and CaN activities in the channel nanoenvironment, which is only made possible by AKAP79/150 scaffolding.


Assuntos
Proteínas de Ancoragem à Quinase A/metabolismo , Canais de Cálcio Tipo L/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Espinhas Dendríticas/metabolismo , Fatores de Transcrição NFATC/metabolismo , Transdução de Sinais , Ativação Transcricional , Animais , Calcineurina/metabolismo , Canais de Cálcio Tipo L/genética , Células Cultivadas , Espinhas Dendríticas/fisiologia , Células HEK293 , Humanos , Camundongos , Ligação Proteica , Ratos
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