Correction: Metastasis Suppressor microRNA-335 Targets the Formin Family of Actin Nucleators.

[This corrects the article DOI: 10.1371/journal.pone.0078428.].

SPECC1L binds the myosin phosphatase complex MYPT1/PP1ß and can regulate its distribution between microtubules and filamentous actin.

The subcellular localization, activity , and substrate specificity of the serine/threonine protein phosphatase 1 catalytic subunit (PP1cat) is mediated through its dynamic association with regulatory subunits in holoenzyme complexes. While some functional overlap is observed for the three human PP1cat isoforms, they also show distinct targeting based on relative preferences for specific regulatory subunits. A well-known example is the preferential association of MYPT1 with PP1ß in the myosin phosphatase complex. In smooth muscle, MYPT1/PP1ß counteracts the muscle contraction induced by phosphorylation of the light chains of myosin by the myosin light chain kinase. This phosphatase complex is also found in nonmuscle cells, where it is targeted to both myosin and nonmyosin substrates and contributes to regulation of the balance of cytoskeletal structure and motility during cell migration and division. Although it remains unclear how MYPT1/PP1ß traffics between microtubule- and actin-associated substrates, our identification of the microtubule- and actin-binding protein SPECC1L in both the PP1ß and MYPT1 interactomes suggests that it is the missing link. Our validation of their association using coimmunoprecipitation and proximity biotinylation assays, together with the strong overlap that we observed for the SPECC1L and MYPT1 interactomes, confirmed that they exist in a stable complex in the cell. We further showed that SPECC1L binds MYPT1 directly and that it can impact the balance of the distribution of the MYPT1/PP1ß complex between the microtubule and filamentous actin networks.

Cooperative assembly of filopodia by the formin FMNL2 and I-BAR domain protein IRTKS.

Filopodia are long finger-like actin-based structures that project out from the plasma membrane as cells navigate and explore their extracellular environment. The initiation of filopodia formation requires release of tension at the plasma membrane followed by the coordinated assembly of long unbranched actin filaments. Filopodia growth is maintained by a tip complex that promotes actin polymerization and protects the growing barbed ends of the actin fibers from capping proteins. Filopodia growth also depends on additional F-actin bundling proteins to stiffen the actin filaments as well as extension of the membrane sheath projecting from the cell periphery. These activities can be provided by a number of actin-binding and membrane-binding proteins including formins such as formin-like 2 (FMNL2) and FMNL3, and Inverse-Bin-Amphiphysin-Rvs (I-BAR) proteins such as IRTKS and IRSp53, but the specific requirement for these proteins in filopodia assembly is not clear. We report here that IRTKS and IRSp53 are FMNL2-binding proteins. Coexpression of FMNL2 with either I-BAR protein promotes cooperative filopodia assembly. We find IRTKS, but not IRSp53, is required for FMNL2-induced filopodia assembly, and FMNL2 and IRTKS are mutually dependent cofactors in this process. Our results suggest that the primary function for FMNL2 during filopodia assembly is binding to the plasma membrane and that regulation of actin dynamics by its formin homology 2 domain is secondary. From these results, we conclude that FMNL2 initiates filopodia assembly via an unexpected novel mechanism, by bending the plasma membrane to recruit IRTKS and thereby nucleate filopodia assembly.

Impact of fish consumption on all-cause mortality in older people with and without dementia: a community-based cohort study.

BACKGROUND: Increased fish consumption reduces the risk of dementia. However, it is unknown whether fish consumption reduced all-cause mortality in people with dementia. The purpose of the study is to investigate the association of fish consumption with all-cause mortality in older people with dementia versus those without dementia. METHODS: Using a standard method of the Geriatric Mental State, we interviewed 4165 participants aged ≥ 60 years who were randomly recruited from five provinces in China during 2007-2009 to collect the baseline data of socio-demography, disease risk factors, histories of disease, and details of dietary intakes, and diagnosed dementia (n = 406). They were followed up for vital status until 2012. RESULTS: The cohort follow-up documented 329 deaths; 61 were in participants with dementia (55.3 per 1000 person-years) and 224 were those without dementia (22.3). In all participants, the risk of all-cause mortality was reduced with fish intake at " ≥ twice a week" (multivariate-adjusted hazard ratio 0.58, 95% CI 0.34-0.96) and at "once a week or less" (0.79, 0.53-1.18) compared to "never eat" over the past two years. In participants without baseline dementia, the corresponding HRs for all-cause mortality were 0.57 (0.33-0.98) and 0.85 (0.55-1.31), while in participants with dementia were 1.36 (0.28-6.60) and 1.05 (0.30-3.66), respectively. CONCLUSION: This study reveals that consumption of fish in older age reduced all-cause mortality in older people without dementia, but not in people with dementia. Fish intake should be increased in older people in general, prior to the development of dementia in the hope of preventing dementia and prolonging life.

Seasonality of Pediatric Mental Health Emergency Department Visits, School, and COVID-19.

OBJECTIVES: The aim of this study was to explore how the academic calendar, and by extension school-year stressors, contributes to the seasonality of pediatric mental health emergency department (ED) visits. METHODS: The authors reviewed all pediatric mental health ED visits at a large urban medical center from 2014 to 2019. Patients who were younger than 18 years at time of presentation, were Durham residents, and had a primary payer of Medicaid were included in the sample population, and the dates of ED visits of the sample population were compared against dates of academic semesters and summer/winter breaks of a relevant school calendar. Of patients with multiple ED visits, only the first ED presentation was included, and descriptive statistics and a rate ratio were used to describe the study group and identify the rate of ED visits during semesters compared with breaks. RESULTS: Among the sample population from 2014 to 2019, there were 1004 first pediatric mental health ED visits. Of these ED visits, the average number of visits per week during summer/winter breaks was 2.2, and the average number of visits per week during academic semester dates was 3.4. The rate of ED visits was significantly greater during academic semesters compared with breaks (Rate Ratio, 1.6; 95% confidence interval, 1.4-2.0; P < 0.001). CONCLUSIONS: Children may be at greater risk of behavioral health crises or having increased mental needs when school is in session. As many children's mental health has worsened during the COVID-19 (coronavirus disease 2019) pandemic, these findings highlight the need for increased mental health services in the school setting as children return to in-person learning. In addition, it may benefit health systems to plan behavioral health staffing around academic calendars.

Biodiversity of Nearctic inland water: discovery of the genus Heterorotula (Porifera, Spongillida, Spongillidae) in the Appalachian Mountains, with biogeographical implications and description of new species.

This paper reports the discovery of a small population of sponges in the Pigeon River of eastern Tennessee, USA, which were morphologically distinct from Spongillida of North America. A morphological comparative analysis resulted in the first Nearctic record of the genus Heterorotula with the description of a new species Heterorotulalucasi sp. nov. diverging from all other known species by its unique combinations of diagnostic morphotraits of spicules and gemmules. The new record enlarges the geographic range of the genus which has been known until now only from Australia, New Zealand, New Caledonia, Japan (as an alien species), and from subequatorial Brazil (as subfossil remains). The discovery of a biogeographic enclave of Heterorotula in the southeastern United States contributes to the understanding of Porifera inland water biodiversity, biogeographic patterns, and adaptive morphotraits in the Nearctic and globally. Data confirm that the Appalachian region (Ordovician-Permian origin) of Tennessee and, in general, of North America have high levels of diversity and endemicity.

Impacts of depression subcase and case on all-cause mortality in older people: The findings from the multi-centre community-based cohort study in China.

OBJECTIVES: It is unclear whether and to what extent depression subcases and cases in older age were associated with all-cause mortality. Little is known about gender differences in the associations. We assess these in older Chinese. METHODS: We examined a random sample of 6124 participants aged ≥60 years across five provinces in China. They were interviewed using a standard method of the GMS-AGECAT to diagnose depression subcase and case and record sociodemographic and disease risk factors at baseline, and to follow up their vital status. We employed Cox regression models to determine all-cause mortality in relation to depression subcases and cases, with adjustment for important variables, including social support and co-morbidities. RESULTS: Over the 10-year follow-up, 928 deaths occurred. Compared to those without depression at baseline, participants with depression subcase (n = 196) and case (n = 264) had increased risk of mortality; adjusted hazard ratios (HRs) were 1.46 (95% CI 1.07-2.00) and 1.45 (1.10-1.91). The adjusted HRs in men were 1.15 (0.72-1.81) and 1.85 (1.22-2.81), and in women 1.87 (1.22-2.87) and 1.22 (0.83-1.77) respectively. In participants aged ≥65 years, the adjusted HRs were 1.12 (0.68-1.84) and 1.99 (1.28-3.10) in men, and 2.06 (1.32-2.24) and 1.41 (0.94-2.10) in women. Increased HR in depression subcases was higher in women than man (ratio of HRs was 1.84, p = 0.034). CONCLUSIONS: Older people with depression subcase could have increased all-cause mortality to a similar extent to those with depression case. More attention should be paid to subcases of depression in women to tackle gender inequalities and improve survival.

Impacts of heart disease, depression and their combination on all-cause mortality in older people: a rural community-based cohort study in China.

OBJECTIVE: To assess the impact of heart disease (HD) combined with depression on all-cause mortality in older people living in the community. DESIGN: A population-based cohort study. PARTICIPANTS: We examined the data of 1429 participants aged ≥60 years recruited in rural areas in Anhui province, China. Using a standard method of interview, we documented all types of HD diagnosed by doctors and used the validated Geriatric Mental Status-Automated Geriatric Examination for Computer Assisted Taxonomy algorithm to diagnose any depression for each participant at baseline in 2003. The participants were followed up for 8 years to identify vital status. MEASUREMENTS: We sought to examine all-cause mortality rates among participants with HD only, depression only and then their combination compared with those without these diseases using multivariate adjusted Cox regression models. RESULTS: 385 deaths occurred in the cohort follow-up. Participants with baseline HD (n=91) had a significantly higher mortality (64.9 per 1000 person-years) than those without HD (42.9). In comparison to those without HD and depression, multivariate adjusted HRs for mortality in the groups of participants who had HD only, depression only and both HD and depression were 1.46 (95% CI 0.98 to 2.17), 1.79 (95% CI 1.28 to 2.48) and 2.59 (95% CI 1.12 to 5.98), respectively. CONCLUSION: Older people with both HD and depression in China had significantly increased all-cause mortality compared with those with HD or depression only, and without either condition. Psychological interventions should be taken into consideration for older people and those with HD living in the community to improve surviving outcome.

Influence of periodontal disease on risk of dementia: a systematic literature review and a meta-analysis.

Periodontal disease (PD) is common and increases cardiovascular diseases. However, it is unclear whether PD is associated with increased risk of dementia. We carried out a systematic review and meta-analysis to investigate the influence of PD on dementia. We projected the number of dementia cases to be saved by reducing PD prevalence in the world. We searched cohort and case-control studies reporting the association of PD with all dementia (or any specific type of dementia) through PubMed, MEDLINE, PsycINFO, SocINDEX, CINHAL, and CNKI until 7th November 2018. Five cohorts and seven case-control studies were identified for review. We pooled eligible data to calculate relative risk (RR) of dementia in relation to PD and computed the number of dementia cases saved through reducing PD prevalence. Of 12 studies, six were undertaken in Asia, four in Europe and two in America. Eleven studies showed a positive association between PD and the risk of dementia, of which 10 were significant, and one reported a non-significant inverse association. Overall their quality was good. Pooled RR of dementia in relation to PD from all high quality studies was 1.38 (95%CI 1.01-1.90); in the five cohorts was 1.18 (1.06-1.31) and in the two case-control studies 2.25 (1.48-3.42). A 50% reduction in the current prevalence of 20% of PD in the population could save 850,000 (630,000-1,420,000) patients with dementia in the world. PD could increase the risk of incident dementia. Preventing and treating PD could contribute to controlling the global epidemic of dementia.

The scaffold-protein IQGAP1 enhances and spatially restricts the actin-nucleating activity of Diaphanous-related formin 1 (DIAPH1).

The actin cytoskeleton is a dynamic array of filaments that undergoes rapid remodeling to drive many cellular processes. An essential feature of filament remodeling is the spatio-temporal regulation of actin filament nucleation. One family of actin filament nucleators, the Diaphanous-related formins, is activated by the binding of small G-proteins such as RhoA. However, RhoA only partially activates formins, suggesting that additional factors are required to fully activate the formin. Here we identify one such factor, IQ motif containing GTPase activating protein-1 (IQGAP1), which enhances RhoA-mediated activation of the Diaphanous-related formin (DIAPH1) and targets DIAPH1 to the plasma membrane. We find that the inhibitory intramolecular interaction within DIAPH1 is disrupted by the sequential binding of RhoA and IQGAP1. Binding of RhoA and IQGAP1 robustly stimulates DIAPH1-mediated actin filament nucleation in vitro In contrast, the actin capping protein Flightless-I, in conjunction with RhoA, only weakly stimulates DIAPH1 activity. IQGAP1, but not Flightless-I, is required to recruit DIAPH1 to the plasma membrane where actin filaments are generated. These results indicate that IQGAP1 enhances RhoA-mediated activation of DIAPH1 in vivo Collectively these data support a model where the combined action of RhoA and an enhancer ensures the spatio-temporal regulation of actin nucleation to stimulate robust and localized actin filament production in vivo.

Actin-based regulation of ciliogenesis - The long and the short of it.

The primary cilia is found on the mammalian cell surface where it serves as an antenna for the reception and transmission of a variety of cellular signaling pathways. At its core the cilium is a microtubule-based organelle, but it is clear that its assembly and function are dependent upon the coordinated regulation of both actin and microtubule dynamics. In particular, the discovery that the centrosome is able to act as both a microtubule and actin organizing centre implies that both cytoskeletal networks are acting directly on the process of cilia assembly. In this review, we set our recent results with the formin FHDC1 in the context of current reports that show each stage of ciliogenesis is impacted by changes in actin dynamics. These include direct effects of actin filament assembly on basal body positioning, vesicle trafficking to and entry into the cilium, cilia length, cilia membrane organization and cilia-dependent signaling.

Autism, Psychosis, or Both? Unraveling Complex Patient Presentations.

Autism spectrum disorders (ASDs) and schizophrenia spectrum disorders co-occur at elevated rates. Although these conditions are diagnostically distinct, they share multiple clinical features and genetic risk factors. This article describes the epidemiologic features and clinical manifestations of psychosis in individuals with ASDs, while also discussing shared genetic risk factors and affected brain regions. Components of a diagnostic assessment, including a thorough developmental, behavioral, medical, and psychiatric history, will be reviewed. The authors highlight the manifestations of catatonia in this population and note the shared features between catatonia and ASDs. Finally, treatment approaches and areas for future study are suggested.

Formins, Golgi, and the Centriole.

Formin homology proteins (formins) are a highly conserved family of cytoskeletal remodeling proteins that are involved in a diverse array of cellular functions. Formins are best known for their ability to regulate actin dynamics, but the same functional domains also govern stability and organization of microtubules. It is thought that this dual activity allows them to coordinate the activity of these two major cytoskeletal networks and thereby influence cellular architecture. Golgi ribbon assembly is dependent upon cooperative interactions between actin filaments and cytoplasmic microtubules originating both at the Golgi itself and from the centrosome. Similarly, centrosome assembly, centriole duplication, and centrosome positioning are also reliant on a dialogue between both cytoskeletal networks. As presented in this chapter, a growing body of evidence suggests that multiple formin proteins play essential roles in these central cellular processes.

Impacts of Overweight and Obesity in Older Age on the Risk of Dementia: A Systematic Literature Review and a Meta-Analysis.

BACKGROUND: It is unclear whether overweight and obesity in older age reduces or increases the risk of incident dementia. OBJECTIVE: To assess the impacts of overweight and obesity in older age on incident dementia. METHODS: We searched cohort studies reporting body weight measured in older age and dementia through PubMed, Embase, Medline, PyschInfo, and Cochrane library until July 2016. Sixteen articles were identified for the review. We pooled data from them and a new unpublished study from China, to calculate relative risk (RR) of incident dementia in relation to body mass index (BMI) and waist circumference (WC). RESULTS: All 16 cohort studies were undertaken in high income countries, with follow-up periods ranging between 3 to 18 years. Thirteen studies showed an inverse association between BMI and dementia, and three studies demonstrated a positive association. Pooled RR of dementia in relation to continuous BMI from 14 studied populations, including the new Chinese data, was 0.97 (95% CI 0.95-1.00); in those followed up <9 years it was 0.95 (0.93-0.96) while in ≥9 years follow-up it was 1.03 (0.96-1.11). In five studied populations examining categorical BMI, RR of dementia in older people classified as overweight and obese was 0.98 (0.54-1.77) and 1.17 (0.65-2.10) respectively, in comparison with other weights. The pooled WC data showed no association between increased WC and reduced risk of dementia. CONCLUSION: The current evidence did not support a paradox on beneficial impacts of overweight and obesity in older age on incident dementia. More studies with long term follow up are needed to clarify the association of body weight in older age with dementia risk.

Pulmonary Infarction: Right Upper Quadrant Pain as a Presenting Symptom With Review of Typical Computed Tomography Imaging Features.

The purpose of this case presentation is to discuss right upper quadrant pain as an atypical presenting symptom in pulmonary infarction and review the typical computed tomography (CT) imaging features of pulmonary infarction to improve diagnostic accuracy. Pulmonary infarction results from occlusion of distal arterial vasculature within the lung parenchyma leading to ischemia, hemorrhage, and ultimately necrosis. Patients with lung infarction typically present with pleuritic chest pain and may have associated signs or symptoms of pulmonary thromboembolism or deep vein thrombosis. In this case study, a 34-yr-old female devoid of any symptoms indicative of either pulmonary embolism or deep vein thrombosis presented with right upper quadrant pain 1 mo status post open reduction internal fixation for a left ankle fracture. Multiple clinic visits spanning approximately 7 d were significant for a right lower lobe opacity seen on CT of the abdomen which was presumed to represent community acquired pneumonia as a source for the patient's RUQ pain. The patient presented to the emergency department 1 wk later (6 wk following her initial surgery) complaining of left lower extremity swelling and was subsequently diagnosed with a left lower extremity DVT via ultrasound. CT of the pulmonary arteries was negative for PE but identified a right lower lobe opacity which in retrospect was consistent with pulmonary infarction.

Actin-dependent regulation of cilia length by the inverted formin FHDC1.

A primary cilium is found on most mammalian cells, where it acts as a cellular antenna for the reception of both mechanical and chemical signals. A variety of diseases are associated with defective ciliogenesis, reflecting the ubiquity of the function of cilia and the number of proteins required for their assembly. Proper cilia length is necessary for cilia signaling and is regulated through a poorly understood balance of assembly and disassembly rates. FHDC1 is a unique member of the formin family of cytoskeletal regulatory proteins. Overexpression of FHDC1 induces F-actin accumulation and microtubule stabilization and acetylation. We find that overexpression of FHDC1 also has profound effects on ciliogenesis; in most cells FHDC1 overexpression blocks cilia assembly, but the cilia that are present are immensely elongated. FHDC1-induced cilia growth requires the FHDC1 FH2 and microtubule-binding domain and results from F-actin-dependent inhibition of cilia disassembly. FHDC1 depletion, or treatment with a pan-formin inhibitor, inhibits cilia assembly and induces cilia resorption. Endogenous FHDC1 protein localizes to cytoplasmic microtubules converging on the base of the cilia, and we identify the subdistal appendage protein Cep170 as an FHDC1 interacting protein. Our results suggest that FHDC1 plays a role in coordinating cytoskeletal dynamics during normal cilia assembly.

Prevalence and determinants of undetected dementia in the community: a systematic literature review and a meta-analysis.

OBJECTIVES: Detection of dementia is essential for improving the lives of patients but the extent of underdetection worldwide and its causes are not known. This study aimed to quantify the prevalence of undetected dementia and to examine its correlates. METHODS/SETTING/PARTICIPANTS: A systematic search was conducted until October 2016 for studies reporting the proportion of undetected dementia and/or its determinants in either the community or in residential care settings worldwide. Random-effects models calculated the pooled rate of undetected dementia and subgroup analyses were conducted to identify determinants of the variation. PRIMARY AND SECONDARY OUTCOME MEASURES: The outcome measures of interest were the prevalence and determinants of undetected dementia. RESULTS: 23 studies were eligible for inclusion in this review. The pooled rate of undetected dementia was 61.7% (95% CI 55.0% to 68.0%). The rate of underdetection was higher in China and India (vs Europe and North America), in the community setting (vs residential/nursing care), age of <70 years, male gender and diagnosis by general practitioner. However, it was lower in the studies using Mini-Mental State Examination (MMSE) diagnosis criteria. CONCLUSIONS: The prevalence of undetected dementia is high globally. Wide variations in detecting dementia need to be urgently examined, particularly in populations with low socioeconomic status. Efforts are required to reduce diagnostic inequality and to improve early diagnosis in the community.

Birth size, risk factors across life and cognition in late life: protocol of prospective longitudinal follow-up of the MYNAH (MYsore studies of Natal effects on Ageing and Health) cohort.

INTRODUCTION: For late-life neurocognitive disorders, as for other late-life chronic diseases, much recent interest has focused on the possible relevance of Developmental Origins of Health and Disease (DOHaD). Programming by undernutrition in utero, followed by overnutrition in adult life may lead to an increased risk, possibly mediated through cardiovascular and metabolic pathways. This study will specifically examine, if lower birth weight is associated with poorer cognitive functioning in late life in a south Indian population. METHODS AND ANALYSIS: From 1934 onwards, the birth weight, length and head circumference of all babies born in the CSI Holdsworth Memorial Hospital, Mysore, India, were recorded in obstetric notes. Approximately 800 men and women from the Mysore Birth Records Cohort aged above 55 years, and a reliable informant for each, will be asked to participate in a single cross-sectional baseline assessment for cognitive function, mental health and cardiometabolic disorders. Participants will be assessed for hypertension, type-2 diabetes and coronary heart disease, nutritional status, health behaviours and lifestyles, family living arrangements, economic status, social support and social networks. Additional investigations include blood tests (for diabetes, insulin resistance, dyslipidaemia, anaemia, vitamin B12 and folate deficiency, hyperhomocysteinemia, renal impairment, thyroid disease and Apolipoprotein E genotype), anthropometry, ECG, blood pressure, spirometry and body composition (bioimpedance). We will develop an analysis plan, first using traditional univariate and multivariable analytical paradigms with independent, dependent and mediating/confounding/interacting variables to test the main hypotheses. ETHICS AND DISSEMINATION: This study has been approved by the research ethics committee of CSI Holdsworth Memorial Hospital. The findings will be disseminated locally and at international meetings, and will be published in open access peer reviewed journals.

A specific FMNL2 isoform is up-regulated in invasive cells.

BACKGROUND: Formins are a highly conserved family of cytoskeletal remodeling proteins. A growing body of evidence suggests that formins play key roles in the progression and spread of a variety of cancers. There are 15 human formin proteins and of these the Diaphanous-Related Formins (DRFs) are the best characterized. Included in the DRFs are the Formin-Like proteins, FMNL1, 2 & 3, each of which have been strongly implicated in driving tumorigenesis and metastasis of specific tumors. In particular, increased FMNL2 expression correlates with increased invasiveness of colorectal cancer (CRC) in vivo and for a variety of CRC cell-lines in vitro. FMNL2 expression is also required for invasive cell motility in other cancer cell-lines. There are multiple alternatively spliced isoforms of FMNL2 and it is predicted that the encoded proteins will differ in their regulation, subcellular localization and in their ability to regulate cytoskeletal dynamics. RESULTS: Using RT-PCR we identified four FMNL2 isoforms expressed in CRC and melanoma cell-lines. We find that a previously uncharacterized FMNL2 isoform is predominantly expressed in a variety of melanoma and CRC cell lines; this isoform is also more effective in driving 3D motility. Building on previous reports, we also show that FMNL2 is required for invasion in A375 and WM266.4 melanoma cells. CONCLUSIONS: Taken together, these results suggest that FMNL2 is likely to be generally required in melanoma cells for invasion, that a specific isoform of FMNL2 is up-regulated in invasive CRC and melanoma cells and this isoform is the most effective at facilitating invasion.

Actin- and microtubule-dependent regulation of Golgi morphology by FHDC1.

The Golgi apparatus is the central hub of intracellular trafficking and consists of tethered stacks of cis, medial, and trans cisternae. In mammalian cells, these cisternae are stitched together as a perinuclear Golgi ribbon, which is required for the establishment of cell polarity and normal subcellular organization. We previously identified FHDC1 (also known as INF1) as a unique microtubule-binding member of the formin family of cytoskeletal-remodeling proteins. We show here that endogenous FHDC1 regulates Golgi ribbon formation and has an apparent preferential association with the Golgi-derived microtubule network. Knockdown of FHDC1 expression results in defective Golgi assembly and suggests a role for FHDC1 in maintenance of the Golgi-derived microtubule network. Similarly, overexpression of FHDC1 induces dispersion of the Golgi ribbon into functional ministacks. This effect is independent of centrosome-derived microtubules and instead likely requires the interaction between the FHDC1 microtubule-binding domain and the Golgi-derived microtubule network. These effects also depend on the interaction between the FHDC1 FH2 domain and the actin cytoskeleton. Thus our results suggest that the coordination of actin and microtubule dynamics by FHDC1 is required for normal Golgi ribbon formation.