Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Small GTPases ; 9(3): 260-273, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-27574848

RESUMO

RhoH is a haematopoietic -specific, GTPase-deficient Rho GTPase that plays an essential role in T lymphocyte development and haematopoietic cell migration. RhoH is known to interact with ZAP70 in T cell receptor (TCR) signaling and antagonize Rac GTPase activity. To further elucidate the molecular mechanisms of RhoH in T cell function, we carried out in vivo biotinylation and mass spectrometry analysis to identify new RhoH-interacting proteins in Jurkat T cells. We indentified Kaiso by streptavidin capture and confirmed the interaction with RhoH by co-immunoprecipitation. Kaiso is a 95 kDa dual-specific Broad complex, Trantrak, Bric-a-brac/Pox virus, Zinc finger (POZ-ZF) transcription factor that has been shown to regulate both gene expression and p120 catenin-associated cell-cell adhesions. We further showed that RhoH, Kaiso and p120 catenin all co-localize at chemokine-induced actin-containing cell protrusion sites. Using RhoH knockdown we demonstrated that Kaiso localization depends on RhoH function. Similar to the effect of RhoH deficiency, Kaiso down-regulation led to altered cell migration and actin-polymerization in chemokine stimulated Jurkat cells. Interestingly, RhoH and Kaiso also co-localized to the nucleus in a time-dependent fashion after chemokine stimulation and with T cell receptor activation where RhoH is required for Kaiso localization. Based on these results and previous studies, we propose that extracellular microenvironment signals regulate RhoH and Kaiso to modulate actin-cytoskeleton structure and transcriptional activity during T cell migration.


Assuntos
Quimiocinas/farmacologia , Citoesqueleto/metabolismo , Linfócitos T/efeitos dos fármacos , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Dedos de Zinco , Proteínas rho de Ligação ao GTP/metabolismo , Actinas/metabolismo , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Células Jurkat , Ligação Proteica , Transporte Proteico/efeitos dos fármacos , Linfócitos T/citologia , Linfócitos T/metabolismo , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética
3.
Nat Cell Biol ; 17(4): 421-33, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25751138

RESUMO

For proper chromosome segregation, sister kinetochores must interact with microtubules from opposite spindle poles (bi-orientation). To establish bi-orientation, aberrant kinetochore-microtubule attachments are disrupted (error correction) by aurora B kinase (Ipl1 in budding yeast). Paradoxically, during this disruption, new attachments are still formed efficiently to enable fresh attempts at bi-orientation. How this is possible remains an enigma. Here we show that kinetochore attachment to the microtubule lattice (lateral attachment) is impervious to aurora B regulation, but attachment to the microtubule plus end (end-on attachment) is disrupted by this kinase. Thus, a new lateral attachment is formed without interference, then converted to end-on attachment and released if incorrect. This process continues until bi-orientation is established and stabilized by tension across sister kinetochores. We reveal how aurora B specifically promotes disruption of the end-on attachment through phospho-regulation of kinetochore components Dam1 and Ndc80. Our results reveal fundamental mechanisms for promoting error correction for bi-orientation.


Assuntos
Proteínas de Ciclo Celular/genética , Cinetocoros/fisiologia , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/fisiologia , Proteínas Nucleares/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Aurora Quinases/genética , Sítios de Ligação , Segregação de Cromossomos/genética , Mitose , Mutação , Ligação Proteica , Fuso Acromático/fisiologia
4.
Dev Cell ; 21(5): 920-33, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22075150

RESUMO

How kinetochores regulate microtubule dynamics to ensure proper kinetochore-microtubule interactions is unknown. Here, we studied this during early mitosis in Saccharomyces cerevisiae. When a microtubule shrinks and its plus end reaches a kinetochore bound to its lateral surface, the microtubule end attempts to tether the kinetochore. This process often fails and, responding to this failure, microtubule rescue (conversion from shrinkage to growth) occurs, preventing kinetochore detachment from the microtubule end. This rescue is promoted by Stu2 transfer (ortholog of vertebrate XMAP215/ch-TOG) from the kinetochore to the microtubule end. Meanwhile, microtubule rescue distal to the kinetochore is also promoted by Stu2, which is transported by a kinesin-8 motor Kip3 along the microtubule from the kinetochore. Microtubule extension following rescue facilitates interaction with other widely scattered kinetochores, diminishing long delays in collecting the complete set of kinetochores by microtubules. Thus, kinetochore-dependent microtubule rescue ensures efficient and sustained kinetochore-microtubule interactions in early mitosis.


Assuntos
Cinetocoros/metabolismo , Microtúbulos/metabolismo , Mitose , Saccharomyces cerevisiae/citologia , Células Cultivadas , Proteínas Associadas aos Microtúbulos/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
5.
Curr Biol ; 21(3): 207-13, 2011 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-21256019

RESUMO

Proper chromosome segregation in mitosis relies on correct kinetochore-microtubule (KT-MT) interactions. The KT initially interacts with the lateral surface of a single MT (lateral attachment) extending from a spindle pole and is subsequently anchored at the plus end of the MT (end-on attachment). The conversion from lateral to end-on attachment is crucial because end-on attachment is more robust and thought to be necessary to sustain KT-MT attachment when tension is applied across sister KTs upon their biorientation. The mechanism for this conversion is still elusive. The Ndc80 complex is an essential component of the KT-MT interface, and here we studied a role of the Ndc80 loop region, a distinct motif looping out from the coiled-coil shaft of the complex, in Saccharomyces cerevisiae. With deletions or mutations of the loop region, the lateral KT-MT attachment occurred normally; however, subsequent conversion to end-on attachment was defective, leading to failure in sister KT biorientation. The Ndc80 loop region was required for Ndc80-Dam1 interaction and KT loading of the Dam1 complex, which in turn supported KT tethering to the dynamic MT plus end. The Ndc80 loop region, therefore, has an important role in the conversion from lateral to end-on attachment, a crucial maturation step of KT-MT interaction.


Assuntos
Cinetocoros/metabolismo , Microtúbulos/metabolismo , Proteínas Nucleares/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/ultraestrutura , Sequência de Aminoácidos , Cinetocoros/química , Cinetocoros/fisiologia , Cinetocoros/ultraestrutura , Microtúbulos/química , Microtúbulos/ultraestrutura , Dados de Sequência Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/fisiologia , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/fisiologia , Alinhamento de Sequência
6.
Oncogene ; 23(22): 3889-97, 2004 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-15021905

RESUMO

The human homologue of the Drosophila discs large tumor suppressor gene (hDlg) is a member of the membrane-associated guanylate kinase family with three PSD-95/Dlg/ZO-1 (PDZ) domains. hDlg has been shown to bind tumor suppressor proteins, adenomatous polyposis coli (APC) and protein tyrosine phosphatase and tensin homologue (PTEN), and several viral oncoproteins, and has been implicated in the negative regulation of cell proliferation. hDlg has furthermore been shown to localize at the plasma membrane of synapses and to scaffold cell surface receptors and channels. In epithelial cells, hDlg localizes at the basolateral plasma membrane, but its localization mechanism is unknown. We searched here for a transmembrane protein that directly bound to hDlg. hDlg bound tumor endothelial marker 5 (TEM5), a seven-pass transmembrane protein that is homologous to the family B of G-protein-coupled receptors (GPCRs). TEM5 has previously been reported to display elevated expression during tumor angiogenesis and neoangiogenesis. The PDZ domains of hDlg bound the C-terminal PDZ-binding motif of TEM5. The expression of TEM5 was detected in endothelial cells of embryonic liver, where hDlg colocalized with TEM5. hDlg furthermore bound a novel seven-pass transmembrane protein, which was homologous to TEM5, and was named here a TEM5-like protein (TEM5-like). These results suggest that hDlg localizes at the plasma membrane through TEM5 and TEM5-like and furthermore scaffolds these GPCRs in endothelial cells during tumor angiogenesis and neoangiogenesis.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Proteínas/metabolismo , Receptores de Superfície Celular/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Sequência de Aminoácidos , Animais , Northern Blotting , Proteína 1 Homóloga a Discs-Large , Humanos , Proteínas de Membrana , Dados de Sequência Molecular , RNA Mensageiro/metabolismo , Receptores de Superfície Celular/genética , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...