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Kjos I, Vestre K, Guadagno NA, Borg Distefano M, Progida C. Rab and Arf proteins at the crossroad between membrane transport and cytoskeleton dynamics. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:1397-1409. [PMID: 30021127 DOI: 10.1016/j.bbamcr.2018.07.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/05/2018] [Accepted: 07/13/2018] [Indexed: 01/04/2023]
Abstract
The intracellular movement and positioning of organelles and vesicles is mediated by the cytoskeleton and molecular motors. Small GTPases like Rab and Arf proteins are main regulators of intracellular transport by connecting membranes to cytoskeleton motors or adaptors. However, it is becoming clear that interactions between these small GTPases and the cytoskeleton are important not only for the regulation of membrane transport. In this review, we will cover our current understanding of the mechanisms underlying the connection between Rab and Arf GTPases and the cytoskeleton, with special emphasis on the double role of these interactions, not only in membrane trafficking but also in membrane and cytoskeleton remodeling. Furthermore, we will highlight the most recent findings about the fine control mechanisms of crosstalk between different members of Rab, Arf, and Rho families of small GTPases in the regulation of cytoskeleton organization.
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Affiliation(s)
- Ingrid Kjos
- Department of Biosciences, University of Oslo, Norway
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52
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Zhao X, Zhang W, Ji W. MYO5A inhibition by miR-145 acts as a predictive marker of occult neck lymph node metastasis in human laryngeal squamous cell carcinoma. Onco Targets Ther 2018; 11:3619-3635. [PMID: 29950866 PMCID: PMC6016585 DOI: 10.2147/ott.s164597] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION Each year, ~50,000 patients worldwide die of laryngeal squamous cell carcinoma (LSCC) because of its highly metastatic properties. However, its pathogenic mechanisms are still unclear, and in particular, the prediction of metastasis remains elusive. This study aimed to define the role of microRNA-145 (miR-145) in LSCC progression. We also aimed to elucidate the clinical significance of the miR-145/MYO5A pathway, especially the predictive function of MYO5A in neck lymph node metastasis. MATERIALS AND METHODS MYO5A and miR-145 expression was analyzed in 132 patients with LSCC, and associations between their expression and clinicopathological features were evaluated. We validated the regulatory relationship between miR-145b and MYO5A by dual luciferase reporter assay. The role of the miR-145/MYO5A pathway in proliferation, metastasis, and apoptosis was examined in vitro. The predictive functions of MYO5A in neck lymph node metastasis and prognosis were defined according to patient follow-up. RESULTS Our results showed downregulation of miR-145 in LSCC, which was negatively correlated with MYO5A suppression of LSCC progression and metastasis. MiR-145 directly regulated MYO5A expression in vitro and suppressed LSCC proliferation and invasion while promoting apoptosis by inhibiting MYO5A. CONCLUSION Notably, overexpression of serum MYO5A in LSCC predicted cervical nodal occult metastasis and poor prognosis, providing an effective indicator for predicting neck lymph node metastasis and assessing LSCC prognosis.
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Affiliation(s)
- Xudong Zhao
- Department of Otorhinolaryngology, Shengjing Hospital, China Medical University, Shenyang, China
| | - Wei Zhang
- Department of Endocrinology, Shengjing Hospital, China Medical University, Shenyang, China
| | - Wenyue Ji
- Department of Otorhinolaryngology, Shengjing Hospital, China Medical University, Shenyang, China
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53
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Torres A, Brownstein CA, Tembulkar SK, Graber K, Genetti C, Kleiman RJ, Sweadner KJ, Mavros C, Liu KX, Smedemark-Margulies N, Maski K, Yang E, Agrawal PB, Shi J, Beggs AH, D'Angelo E, Lincoln SH, Carroll D, Dedeoglu F, Gahl WA, Biggs CM, Swoboda KJ, Berry GT, Gonzalez-Heydrich J. De novo ATP1A3 and compound heterozygous NLRP3 mutations in a child with autism spectrum disorder, episodic fatigue and somnolence, and muckle-wells syndrome. Mol Genet Metab Rep 2018; 16:23-29. [PMID: 29922587 PMCID: PMC6005789 DOI: 10.1016/j.ymgmr.2018.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/02/2018] [Indexed: 11/28/2022] Open
Abstract
Complex phenotypes may represent novel syndromes that are the composite interaction of several genetic and environmental factors. We describe an 9-year old male with high functioning autism spectrum disorder and Muckle-Wells syndrome who at age 5 years of age manifested perseverations that interfered with his functioning at home and at school. After age 6, he developed intermittent episodes of fatigue and somnolence lasting from hours to weeks that evolved over the course of months to more chronic hypersomnia. Whole exome sequencing showed three mutations in genes potentially involved in his clinical phenotype. The patient has a predicted pathogenic de novo heterozygous p.Ala681Thr mutation in the ATP1A3 gene (chr19:42480621C>T, GRCh37/hg19). Mutations in this gene are known to cause Alternating Hemiplegia of Childhood, Rapid Onset Dystonia Parkinsonism, and CAPOS syndrome, sometimes accompanied by autistic features. The patient also has compound heterozygosity for p.Arg490Lys/p.Val200Met mutations in the NLRP3 gene (chr1:247588214G>A and chr1:247587343G>A, respectively). NLRP3 mutations are associated in an autosomal dominant manner with clinically overlapping auto-inflammatory conditions including Muckle-Wells syndrome. The p.Arg490Lys is a known pathogenic mutation inherited from the patient's father. The p.Val200Met mutation, inherited from his mother, is a variant of unknown significance (VUS). Whether the de novoATP1A3mutation is responsible for or plays a role in the patient's episodes of fatigue and somnolence remains to be determined. The unprecedented combination of two NLRP3 mutations may be responsible for other aspects of his complex phenotype.
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Affiliation(s)
- Alcy Torres
- Department of Neurology, Boston University Medical Center, Boston, MA 02118, USA
| | - Catherine A. Brownstein
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Tommy Fuss Center for Neuropsychiatric Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Corresponding author at: Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
| | - Sahil K. Tembulkar
- Tommy Fuss Center for Neuropsychiatric Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Developmental Neuropsychiatry Clinic, Department of Psychiatry, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kelsey Graber
- Tommy Fuss Center for Neuropsychiatric Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Developmental Neuropsychiatry Clinic, Department of Psychiatry, Boston Children's Hospital, Boston, MA 02115, USA
| | - Casie Genetti
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
| | - Robin J. Kleiman
- Harvard Medical School, Boston, MA 02115, USA
- Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kathleen J. Sweadner
- Harvard Medical School, Boston, MA 02115, USA
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Chrystal Mavros
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
| | | | | | - Kiran Maski
- Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Edward Yang
- Harvard Medical School, Boston, MA 02115, USA
- Department of Radiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Pankaj B. Agrawal
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Jiahai Shi
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong Special Administrative Region
| | - Alan H. Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Eugene D'Angelo
- Tommy Fuss Center for Neuropsychiatric Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Developmental Neuropsychiatry Clinic, Department of Psychiatry, Boston Children's Hospital, Boston, MA 02115, USA
| | - Sarah Hope Lincoln
- Harvard Medical School, Boston, MA 02115, USA
- Developmental Neuropsychiatry Clinic, Department of Psychiatry, Boston Children's Hospital, Boston, MA 02115, USA
| | - Devon Carroll
- Developmental Neuropsychiatry Clinic, Department of Psychiatry, Boston Children's Hospital, Boston, MA 02115, USA
| | - Fatma Dedeoglu
- Division of Immunology, Boston Children's Hospital, Boston, MA 02115, USA
| | - William A. Gahl
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Catherine M. Biggs
- Harvard Medical School, Boston, MA 02115, USA
- Division of Immunology, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Kathryn J. Swoboda
- Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Gerard T. Berry
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Joseph Gonzalez-Heydrich
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Tommy Fuss Center for Neuropsychiatric Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Corresponding author at: Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
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54
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No novel, high penetrant gene might remain to be found in Japanese patients with unknown MODY. J Hum Genet 2018; 63:821-829. [PMID: 29670293 DOI: 10.1038/s10038-018-0449-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/07/2018] [Accepted: 03/09/2018] [Indexed: 11/08/2022]
Abstract
MODY 5 and 6 have been shown to be low-penetrant MODYs. As the genetic background of unknown MODY is assumed to be similar, a new analytical strategy is applied here to elucidate genetic predispositions to unknown MODY. We examined to find whether there are major MODY gene loci remaining to be identified using SNP linkage analysis in Japanese. Whole-exome sequencing was performed with seven families with typical MODY. Candidates for novel MODY genes were examined combined with in silico network analysis. Some peaks were found only in either parametric or non-parametric analysis; however, none of these peaks showed a LOD score greater than 3.7, which is approved to be the significance threshold of evidence for linkage. Exome sequencing revealed that three mutated genes were common among 3 families and 42 mutated genes were common in two families. Only one of these genes, MYO5A, having rare amino acid mutations p.R849Q and p.V1601G, was involved in the biological network of known MODY genes through the intermediary of the INS. Although only one promising candidate gene, MYO5A, was identified, no novel, high penetrant MODY genes might remain to be found in Japanese MODY.
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55
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Sefsafi Z, Hasbaoui BE, Kili A, Agadr A, Khattab M. Macrophage activation syndrome associated with griscelli syndrome type 2: case report and review of literature. Pan Afr Med J 2018; 29:75. [PMID: 29875956 PMCID: PMC5987098 DOI: 10.11604/pamj.2018.29.75.12353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 12/19/2017] [Indexed: 11/13/2022] Open
Abstract
Macrophage activation syndrome (MAS) is a severe and potentially fatal life-threatening condition associated with excessive activation and expansion of T cells with macrophages and a high expression of cytokines, resulting in an uncontrolled inflammatory response, with high levels of macrophage colony-stimulating factor and causing multiorgan damage. This syndrome is classified into primary (genetic/familial) or secondary forms to several etiologies, such as infections, neoplasias mainly hemopathies or autoimmune diseases. It is characterised clinically by unremitting high fever, pancytopaenia, hepatosplenomegaly, hepatic dysfunction, encephalopathy, coagulation abnormalities and sharply increased levels of ferritin. The pathognomonic feature of the syndrome is seen on bone marrow examination, which frequently, though not always, reveals numerous morphologically benign macrophages exhibiting haemophagocytic activity. Because MAS can follow a rapidly fatal course, prompt recognition of its clinical and laboratory features and immediate therapeutic intervention are essential. However, it is difficult to distinguish underlying disease flare, infectious complications or medication side effects from MAS. Although, the pathogenesis of MAS is unclear, the hallmark of the syndrome is an uncontrolled activation and proliferation of T lymphocytes and macrophages, leading to massive hypersecretion of pro-inflammatory cytokines. Mutations in cytolytic pathway genes are increasingly being recognised in children who develop MAS in his secondary form. We present here a case of Macrophage activation syndrome associated with Griscelli syndrome type 2 in a 3-years-old boy who had been referred due to severe sepsis with non-remitting high fever, generalized lymphoadenopathy and hepato-splenomegaly. Laboratory data revealed pancytopenia with high concentrations of triglycerides, ferritin and lactic dehydrogenase while the bone marrow revealed numerous morphologically benign macrophages with haemophagocytic activity that comforting the diagnosis of a SAM according to Ravelli and HLH-2004 criteria. Griscelli syndrome (GS) was evoked on; consanguineous family, recurrent infection, very light silvery-gray color of the hair and eyebrows, Light microscopy examination of the hair showed large, irregular clumps of pigments characteristic of GS. The molecular biology showed mutation in RAB27A gene confirming the diagnosis of a Griscelli syndrome type 2. The first-line therapy was based on the parenteral administration of high doses of corticosteroids, associated with immunosuppressive drugs, cyclosporine A and etoposide waiting for bone marrow transplantation (BMT).
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Affiliation(s)
- Zakia Sefsafi
- Center for Hematology and Oncology Paediatrics, Children's hospital, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Brahim El Hasbaoui
- Department of Pediatrics, Military Teaching Hospital Mohammed V, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Amina Kili
- Center for Hematology and Oncology Paediatrics, Children's hospital, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Aomar Agadr
- Department of Pediatrics, Military Teaching Hospital Mohammed V, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Mohammed Khattab
- Center for Hematology and Oncology Paediatrics, Children's hospital, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
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56
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Bauer A, Kehl A, Jagannathan V, Leeb T. A novel MLPH variant in dogs with coat colour dilution. Anim Genet 2018; 49:94-97. [PMID: 29349785 DOI: 10.1111/age.12632] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2017] [Indexed: 11/28/2022]
Abstract
Coat colour dilution may be the result of altered melanosome transport in melanocytes. Loss-of-function variants in the melanophilin gene (MLPH) cause a recessively inherited form of coat colour dilution in many mammalian and avian species including the dog. MLPH corresponds to the D locus in many domestic animals, and recessive alleles at this locus are frequently denoted with d. In this study, we investigated dilute coloured Chow Chows whose coat colour could not be explained by their genotype at the previously known MLPH:c.-22G>A variant. Whole genome sequencing of such a dilute Chow Chow revealed another variant in the MLPH gene: MLPH:c.705G>C. We propose to designate the corresponding mutant alleles at these two variants d1 and d2 . We performed an association study in a cohort of 15 dilute and 28 non-dilute Chow Chows. The dilute dogs were all either compound heterozygous d1 /d2 or homozygous d2 /d2 , whereas the non-dilute dogs carried at least one wildtype allele D. The d2 allele did not occur in 417 dogs from diverse other breeds. However, when we genotyped a Sloughi family, in which a dilute coloured puppy had been born out of non-dilute parents, we again observed perfect co-segregation of the newly discovered d2 allele with coat colour dilution. Finally, we identified a blue Thai Ridgeback with the d1 /d2 genotype. Thus, our data identify the MLPH:c.705G>C as a variant explaining a second canine dilution allele. Although relatively rare overall, this d2 allele is segregating in at least three dog breeds, Chow Chows, Sloughis and Thai Ridgebacks.
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Affiliation(s)
- A Bauer
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.,DermFocus, University of Bern, 3001, Bern, Switzerland
| | - A Kehl
- Laboklin, 97688, Bad Kissingen, Germany
| | - V Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.,DermFocus, University of Bern, 3001, Bern, Switzerland
| | - T Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.,DermFocus, University of Bern, 3001, Bern, Switzerland
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57
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Landrock KK, Sullivan P, Martini-Stoica H, Goldstein DS, Graham BH, Yamamoto S, Bellen HJ, Gibbs RA, Chen R, D'Amelio M, Stoica G. Pleiotropic neuropathological and biochemical alterations associated with Myo5a mutation in a rat Model. Brain Res 2017; 1679:155-170. [PMID: 29217155 DOI: 10.1016/j.brainres.2017.11.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 12/20/2022]
Abstract
In this study, we analyze the neuropathological and biochemical alterations involved in the pathogenesis of a neurodegenerative/movement disorder during different developmental stages in juvenile rats with a mutant Myosin5a (Myo5a). In mutant rats, a spontaneous autosomal recessive mutation characterized by the absence of Myo5a protein expression in the brain is associated with a syndrome of locomotor dysfunction, altered coat color, and neuroendocrine abnormalities. Myo5a encodes a myosin motor protein required for transport and proper distribution of subcellular organelles in somatodendritic processes in neurons. Here we report marked hyperphosphorylation of alpha-synuclein and tau, as well as region-specific buildup of the autotoxic dopamine metabolite, 3,4-dihydroxyphenyl-acetaldehyde (DOPAL), related to decreased aldehyde dehydrogenases activity and neurodegeneration in mutant rats. Alpha-synuclein accumulation in mitochondria of dopaminergic neurons is associated with impaired enzymatic respiratory complex I and IV activity. The behavioral and biochemical lesions progress after 15 days postnatal, and by 30-40 days the animals must be euthanized because of neurological impairment. Based on the obtained results, we propose a pleiotropic pathogenesis that links the Myo5a gene mutation to deficient neuronal development and progressive neurodegeneration. This potential model of a neurodevelopmental disorder with neurodegeneration and motor deficits may provide further insight into molecular motors and their associated proteins responsible for altered neurogenesis and neuronal disease pathogenesis.
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Affiliation(s)
- Kerstin K Landrock
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA.
| | - Patti Sullivan
- Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Heidi Martini-Stoica
- Interdepartmental Program of Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA.
| | - David S Goldstein
- Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA.
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA.
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA.
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA.
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA.
| | - Marcello D'Amelio
- University Campus Bio-Medico, Department of Medicine, Unit of Molecular Neurosciences, Rome, Italy.
| | - George Stoica
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA.
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58
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Lombardo AT, Nelson SR, Ali MY, Kennedy GG, Trybus KM, Walcott S, Warshaw DM. Myosin Va molecular motors manoeuvre liposome cargo through suspended actin filament intersections in vitro. Nat Commun 2017; 8:15692. [PMID: 28569841 PMCID: PMC5461480 DOI: 10.1038/ncomms15692] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 04/13/2017] [Indexed: 01/15/2023] Open
Abstract
Intracellular cargo transport relies on myosin Va molecular motor ensembles to travel along the cell's three-dimensional (3D) highway of actin filaments. At actin filament intersections, the intersecting filament is a structural barrier to and an alternate track for directed cargo transport. Here we use 3D super-resolution fluorescence imaging to determine the directional outcome (that is, continues straight, turns or terminates) for an ∼10 motor ensemble transporting a 350 nm lipid-bound cargo that encounters a suspended 3D actin filament intersection in vitro. Motor–cargo complexes that interact with the intersecting filament go straight through the intersection 62% of the time, nearly twice that for turning. To explain this, we develop an in silico model, supported by optical trapping data, suggesting that the motors' diffusive movements on the vesicle surface and the extent of their engagement with the two intersecting actin tracks biases the motor–cargo complex on average to go straight through the intersection. Cellular cargo transported along actin filaments is faced with a directional choice at an intersection. Here the authors show that myosin Va-bound cargo prefers to go straight through the intersection, and propose a model to explain this by a tug-of-war between motors on the lipid cargo that engage the actin tracks.
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Affiliation(s)
- Andrew T Lombardo
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
| | - Shane R Nelson
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
| | - M Yusuf Ali
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
| | - Guy G Kennedy
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
| | - Sam Walcott
- Department of Mathematics, University of California, Davis, California 95616, USA
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
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59
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Assis LHP, Silva-Junior RMP, Dolce LG, Alborghetti MR, Honorato RV, Nascimento AFZ, Melo-Hanchuk TD, Trindade DM, Tonoli CCC, Santos CT, Oliveira PSL, Larson RE, Kobarg J, Espreafico EM, Giuseppe PO, Murakami MT. The molecular motor Myosin Va interacts with the cilia-centrosomal protein RPGRIP1L. Sci Rep 2017; 7:43692. [PMID: 28266547 PMCID: PMC5339802 DOI: 10.1038/srep43692] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/30/2017] [Indexed: 12/31/2022] Open
Abstract
Myosin Va (MyoVa) is an actin-based molecular motor abundantly found at the centrosome. However, the role of MyoVa at this organelle has been elusive due to the lack of evidence on interacting partners or functional data. Herein, we combined yeast two-hybrid screen, biochemical studies and cellular assays to demonstrate that MyoVa interacts with RPGRIP1L, a cilia-centrosomal protein that controls ciliary signaling and positioning. MyoVa binds to the C2 domains of RPGRIP1L via residues located near or in the Rab11a-binding site, a conserved site in the globular tail domain (GTD) from class V myosins. According to proximity ligation assays, MyoVa and RPGRIP1L can interact near the cilium base in ciliated RPE cells. Furthermore, we showed that RPE cells expressing dominant-negative constructs of MyoVa are mostly unciliated, providing the first experimental evidence about a possible link between this molecular motor and cilia-related processes.
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Affiliation(s)
- L H P Assis
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil.,Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - R M P Silva-Junior
- Department of Cell and Molecular Biology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - L G Dolce
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil.,Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - M R Alborghetti
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - R V Honorato
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - A F Z Nascimento
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil.,Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - T D Melo-Hanchuk
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - D M Trindade
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - C C C Tonoli
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - C T Santos
- Department of Cell and Molecular Biology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - P S L Oliveira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - R E Larson
- Department of Cell and Molecular Biology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - J Kobarg
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - E M Espreafico
- Department of Cell and Molecular Biology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - P O Giuseppe
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - M T Murakami
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil
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Lee J, Eldeeb M, Hsu CK, Saito R, Abouzeid S, McGrath J. Further evidence for genotype-phenotype disparity in Griscelli syndrome. Br J Dermatol 2017; 176:1086-1089. [DOI: 10.1111/bjd.14866] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J.Y.W. Lee
- St John's Institute of Dermatology; King's College London; London U.K
| | - M.S. Eldeeb
- Department of Dermatology, Venereology and Andrology; Faculty of Medicine; Alexandria University; Alexandria Egypt
| | - C.-K. Hsu
- St John's Institute of Dermatology; King's College London; London U.K
- Department of Dermatology; College of Medicine; National Cheng Kung University; Tainan Taiwan
- Institute of Clinical Medicine; College of Medicine; National Cheng Kung University; Tainan Taiwan
| | - R. Saito
- St John's Institute of Dermatology; King's College London; London U.K
- Department of Dermatology; Hiroshima University; Hiroshima Japan
| | - S.A. Abouzeid
- Department of Dermatology, Venereology and Andrology; Faculty of Medicine; Alexandria University; Alexandria Egypt
| | - J.A. McGrath
- St John's Institute of Dermatology; King's College London; London U.K
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Masters TA, Kendrick-Jones J, Buss F. Myosins: Domain Organisation, Motor Properties, Physiological Roles and Cellular Functions. Handb Exp Pharmacol 2017; 235:77-122. [PMID: 27757761 DOI: 10.1007/164_2016_29] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myosins are cytoskeletal motor proteins that use energy derived from ATP hydrolysis to generate force and movement along actin filaments. Humans express 38 myosin genes belonging to 12 classes that participate in a diverse range of crucial activities, including muscle contraction, intracellular trafficking, cell division, motility, actin cytoskeletal organisation and cell signalling. Myosin malfunction has been implicated a variety of disorders including deafness, hypertrophic cardiomyopathy, Usher syndrome, Griscelli syndrome and cancer. In this chapter, we will first discuss the key structural and kinetic features that are conserved across the myosin family. Thereafter, we summarise for each member in turn its unique functional and structural adaptations, cellular roles and associated pathologies. Finally, we address the broad therapeutic potential for pharmacological interventions that target myosin family members.
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Affiliation(s)
- Thomas A Masters
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | | | - Folma Buss
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
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Cheeseman LP, Boulanger J, Bond LM, Schuh M. Two pathways regulate cortical granule translocation to prevent polyspermy in mouse oocytes. Nat Commun 2016; 7:13726. [PMID: 27991490 PMCID: PMC5187413 DOI: 10.1038/ncomms13726] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 10/27/2016] [Indexed: 12/20/2022] Open
Abstract
An egg must be fertilized by a single sperm only. To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules. These translocate from the oocyte's centre to the plasma membrane during meiosis. However, very little is known about the mechanism of cortical granule translocation. Here we investigate cortical granule transport and dynamics in live mammalian oocytes by using Rab27a as a marker. We show that two separate mechanisms drive their transport: myosin Va-dependent movement along actin filaments, and an unexpected vesicle hitchhiking mechanism by which cortical granules bind to Rab11a vesicles powered by myosin Vb. Inhibiting cortical granule translocation severely impaired the block to sperm entry, suggesting that translocation defects could contribute to miscarriages that are caused by polyspermy.
Mammalian eggs release cortical granules to avoid being fertilized by more than a single sperm as polyspermy results in nonviable embryos. Here, the authors describe the mechanism driving translocation of the granules to the cortex in the mouse egg and show this process is essential to prevent polyspermy.
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Affiliation(s)
- Liam P Cheeseman
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Jérôme Boulanger
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Lisa M Bond
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Melina Schuh
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.,Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany
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63
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Lemmelä S, Solovieva S, Shiri R, Benner C, Heliövaara M, Kettunen J, Anttila V, Ripatti S, Perola M, Seppälä I, Juonala M, Kähönen M, Salomaa V, Viikari J, Raitakari OT, Lehtimäki T, Palotie A, Viikari-Juntura E, Husgafvel-Pursiainen K. Genome-Wide Meta-Analysis of Sciatica in Finnish Population. PLoS One 2016; 11:e0163877. [PMID: 27764105 PMCID: PMC5072673 DOI: 10.1371/journal.pone.0163877] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 09/15/2016] [Indexed: 12/14/2022] Open
Abstract
Sciatica or the sciatic syndrome is a common and often disabling low back disorder in the working-age population. It has a relatively high heritability but poorly understood molecular mechanisms. The Finnish population is a genetic isolate where small founder population and bottleneck events have led to enrichment of certain rare and low frequency variants. We performed here the first genome-wide association (GWAS) and meta-analysis of sciatica. The meta-analysis was conducted across two GWAS covering 291 Finnish sciatica cases and 3671 controls genotyped and imputed at 7.7 million autosomal variants. The most promising loci (p<1x10-6) were replicated in 776 Finnish sciatica patients and 18,489 controls. We identified five intragenic variants, with relatively low frequencies, at two novel loci associated with sciatica at genome-wide significance. These included chr9:14344410:I (rs71321981) at 9p22.3 (NFIB gene; p = 1.30x10-8, MAF = 0.08) and four variants at 15q21.2: rs145901849, rs80035109, rs190200374 and rs117458827 (MYO5A; p = 1.34x10-8, MAF = 0.06; p = 2.32x10-8, MAF = 0.07; p = 3.85x10-8, MAF = 0.06; p = 4.78x10-8, MAF = 0.07, respectively). The most significant association in the meta-analysis, a single base insertion rs71321981 within the regulatory region of the transcription factor NFIB, replicated in an independent Finnish population sample (p = 0.04). Despite identifying 15q21.2 as a promising locus, we were not able to replicate it. It was differentiated; the lead variants within 15q21.2 were more frequent in Finland (6–7%) than in other European populations (1–2%). Imputation accuracies of the three significantly associated variants (chr9:14344410:I, rs190200374, and rs80035109) were validated by genotyping. In summary, our results suggest a novel locus, 9p22.3 (NFIB), which may be involved in susceptibility to sciatica. In addition, another locus, 15q21.2, emerged as a promising one, but failed to replicate.
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Affiliation(s)
- Susanna Lemmelä
- Health and Work Ability, Finnish Institute of Occupational Health, 00250 Helsinki, Finland
| | - Svetlana Solovieva
- Health and Work Ability, Finnish Institute of Occupational Health, 00250 Helsinki, Finland
| | - Rahman Shiri
- Health and Work Ability, Finnish Institute of Occupational Health, 00250 Helsinki, Finland
| | - Christian Benner
- Institute for Molecular Medicine Finland (FIMM), 00014 University of Helsinki, Helsinki, Finland
- Department of Public Health, 00014 University of Helsinki, Helsinki, Finland
| | - Markku Heliövaara
- Population Health Unit, National Institute for Health and Welfare, 00251 Helsinki, Finland
| | - Johannes Kettunen
- Faculty of Medicine, Institute of Health Sciences, University of Oulu, 90220 Oulu, Finland
- NMR Metabolomics Laboratory, University of Eastern Finland, Kuopio, Finland
- National Institute for Health and Welfare, Helsinki, Finland
| | - Verneri Anttila
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States of America
| | - Samuli Ripatti
- Institute for Molecular Medicine Finland (FIMM), 00014 University of Helsinki, Helsinki, Finland
- Department of Public Health, 00014 University of Helsinki, Helsinki, Finland
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, CB10 1SA, United Kingdom
| | - Markus Perola
- Institute for Molecular Medicine Finland (FIMM), 00014 University of Helsinki, Helsinki, Finland
- Public Health Genomics Unit, Department of Chronic Disease Prevention, National Institute for Health and Welfare, 00271 Helsinki, Finland
- The Estonian Genome Center, University of Tartu, 51010 Tartu, Estonia
| | - Ilkka Seppälä
- Department of Clinical Chemistry, Fimlab Laboratories, University of Tampere School of Medicine, 33520 Tampere, Finland
| | - Markus Juonala
- Division of Medicine, Turku University Hospital, 20521 Turku, Finland
- Department of Medicine, University of Turku, 20521 Turku, Finland
| | - Mika Kähönen
- Department of Clinical Physiology, Tampere University Hospital, 33521 Tampere, Finland
| | - Veikko Salomaa
- Department of Health, National Institute for Health and Welfare, 00251 Helsinki, Finland
| | - Jorma Viikari
- Division of Medicine, Turku University Hospital, 20521 Turku, Finland
- Department of Medicine, University of Turku, 20521 Turku, Finland
| | - Olli T. Raitakari
- Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, 20520 Turku, Finland
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, 20521 Turku, Finland
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, University of Tampere School of Medicine, 33520 Tampere, Finland
| | - Aarno Palotie
- Institute for Molecular Medicine Finland (FIMM), 00014 University of Helsinki, Helsinki, Finland
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States of America
- Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts 02114, United States of America
| | - Eira Viikari-Juntura
- Disability Prevention Centre, Finnish Institute of Occupational Health, 00250 Helsinki, Finland
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64
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O'Connor E, Töpf A, Müller JS, Cox D, Evangelista T, Colomer J, Abicht A, Senderek J, Hasselmann O, Yaramis A, Laval SH, Lochmüller H. Identification of mutations in the MYO9A gene in patients with congenital myasthenic syndrome. Brain 2016; 139:2143-53. [PMID: 27259756 PMCID: PMC4958899 DOI: 10.1093/brain/aww130] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 04/20/2016] [Indexed: 12/13/2022] Open
Abstract
Congenital myasthenic syndromes are a group of rare and genetically heterogenous disorders resulting from defects in the structure and function of the neuromuscular junction. Patients with congenital myasthenic syndrome exhibit fatigable muscle weakness with a variety of accompanying phenotypes depending on the protein affected. A cohort of patients with a clinical diagnosis of congenital myasthenic syndrome that lacked a genetic diagnosis underwent whole exome sequencing in order to identify genetic causation. Missense biallelic mutations in the MYO9A gene, encoding an unconventional myosin, were identified in two unrelated families. Depletion of MYO9A in NSC-34 cells revealed a direct effect of MYO9A on neuronal branching and axon guidance. Morpholino-mediated knockdown of the two MYO9A orthologues in zebrafish, myo9aa/ab, demonstrated a requirement for MYO9A in the formation of the neuromuscular junction during development. The morphants displayed shortened and abnormally branched motor axons, lack of movement within the chorion and abnormal swimming in response to tactile stimulation. We therefore conclude that MYO9A deficiency may affect the presynaptic motor axon, manifesting in congenital myasthenic syndrome. These results highlight the involvement of unconventional myosins in motor axon functionality, as well as the need to look outside traditional neuromuscular junction-specific proteins for further congenital myasthenic syndrome candidate genes.
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Affiliation(s)
- Emily O'Connor
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Ana Töpf
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Juliane S Müller
- 2 Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Daniel Cox
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Teresinha Evangelista
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Jaume Colomer
- 3 Neuromuscular Unit, Neurology Department, Fundación Sant Joan de Déu, Hospital Materno-Infantil Sant Joan de Déu, Passeig Sant Joan de Déu, 2, 08950 Esplugues de Llobregat, Barcelona, Spain
| | - Angela Abicht
- 4 Friedrich-Baur-Institute, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Jan Senderek
- 4 Friedrich-Baur-Institute, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Oswald Hasselmann
- 5 Children's Hospital of Eastern Switzerland, Department of Neuropediatrics, Claudiusstrasse 6, 9006 St. Gallen, Switzerland
| | - Ahmet Yaramis
- 6 Paediatric Neurology Unit, Diyarbakır Memorial Hospital, Turkey
| | - Steven H Laval
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Hanns Lochmüller
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
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Abstract
The ROS1 gene belongs to the sevenless subfamily of tyrosine kinase insulin receptor genes. A literature review identified a ROS1 fusion in 2.54% of the patients with lung adenocarcinoma and even higher frequencies in spitzoid neoplasms and inflammatory myofibroblastic tumors. At present, 26 genes were found to fuse with ROS1, some of them already known to fuse with RET and ALK. All the fusion proteins retain the ROS1 kinase domain, but rarely its transmembrane domain. Most of the partners have dimerization domains that are retained in the fusion, presumably leading to constitutive ROS1 tyrosine kinase activation. Some partners have transmembrane domains that are retained or not in the chimeric proteins. Therefore, different ROS1 fusions have distinct subcellular localization, suggesting that they may activate different substrates in vivo.
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Affiliation(s)
- Arnaud Uguen
- Faculté de Médecine et des Sciences de la Santé, Université de Brest, Brest, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U1078, Brest, France.,Service d'Anatomie et Cytologie Pathologiques, Hôpital Morvan, CHRU Brest, Brest, France
| | - Marc De Braekeleer
- Faculté de Médecine et des Sciences de la Santé, Université de Brest, Brest, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U1078, Brest, France.,Service de Cytogénétique et Biologie de la Reproduction, Hôpital Morvan, CHRU Brest, Brest, France
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66
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Griscelli syndrome type 2 – A case report and clinical approach to silver blonde hair. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2016. [DOI: 10.1016/j.ejmhg.2015.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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67
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Byrne S, Dionisi-Vici C, Smith L, Gautel M, Jungbluth H. Vici syndrome: a review. Orphanet J Rare Dis 2016; 11:21. [PMID: 26927810 PMCID: PMC4772338 DOI: 10.1186/s13023-016-0399-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 02/08/2016] [Indexed: 11/29/2022] Open
Abstract
Vici syndrome [OMIM242840] is a severe, recessively inherited congenital disorder characterized by the principal features of callosal agenesis, cataracts, oculocutaneous hypopigmentation, cardiomyopathy, and a combined immunodeficiency. Profound developmental delay, progressive failure to thrive and acquired microcephaly are almost universal, suggesting an evolving (neuro) degenerative component. In most patients there is additional variable multisystem involvement that may affect virtually any organ system, including lungs, thyroid, liver and kidneys. A skeletal myopathy is consistently associated, and characterized by marked fibre type disproportion, increase in internal nuclei, numerous vacuoles, abnormal mitochondria and glycogen storage. Life expectancy is markedly reduced.Vici syndrome is due to recessive mutations in EPG5 on chromosome 18q12.3, encoding ectopic P granules protein 5 (EPG5), a key autophagy regulator in higher organisms. Autophagy is a fundamental cellular degradative pathway conserved throughout evolution with important roles in the removal of defective proteins and organelles, defence against infections and adaptation to changing metabolic demands. Almost 40 EPG mutations have been identified to date, most of them truncating and private to individual families.The differential diagnosis of Vici syndrome includes a number of syndromes with overlapping clinical features, neurological and metabolic disorders with shared CNS abnormalities (in particular callosal agenesis), and primary neuromuscular disorders with a similar muscle biopsy appearance. Vici syndrome is also the most typical example of a novel group of inherited neurometabolic conditions, congenital disorders of autophagy.Management is currently largely supportive and symptomatic but better understanding of the underlying autophagy defect will hopefully inform the development of targeted therapies in future.
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Affiliation(s)
- Susan Byrne
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK
| | - Carlo Dionisi-Vici
- Division of Metabolism and Laboratory of Molecular Medicine, Bambino Gesu Children's Hospital IRCCS, Rome, Italy
| | - Luke Smith
- Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK
| | - Mathias Gautel
- Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK.
- Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK.
- Department of Clinical and Basic Neuroscience, IoPPN, King's College, London, UK.
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68
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Making the invisible visible. Semin Cell Dev Biol 2016; 52:58-65. [PMID: 26877141 DOI: 10.1016/j.semcdb.2016.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/08/2016] [Accepted: 02/08/2016] [Indexed: 12/13/2022]
Abstract
In this review, I will discuss how careful scrutiny of genetic skin disorders could help us to understand human biology. Like other organs, the skin and its appendages, such as hairs and teeth, experience fundamental biological processes ranging from lipid metabolism to vesicular transport and cellular migration. However, in contrast to other organ systems, they are accessible and can be studied with relative ease. By visually revealing the functional consequences of single gene defects, genetic skin diseases offer a unique opportunity to study human biology. Here, I will illustrate this concept by discussing how human genetic disorders of skin pigmentation reflect the mechanisms underlying this complex and vital process.
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69
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Voss M, Bryceson YT. Natural killer cell biology illuminated by primary immunodeficiency syndromes in humans. Clin Immunol 2015; 177:29-42. [PMID: 26592356 DOI: 10.1016/j.clim.2015.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/22/2015] [Accepted: 11/14/2015] [Indexed: 12/21/2022]
Abstract
Natural killer (NK) cells are innate immune cytotoxic effector cells well known for their role in antiviral immunity and tumor immunosurveillance. In parts, this knowledge stems from rare inherited immunodeficiency disorders in humans that abrogate NK cell function leading to immune impairments, most notably associated with a high susceptibility to viral infections. Phenotypically, these disorders range from deficiencies selectively affecting NK cells to complex general immune defects that affect NK cells but also other immune cell subsets. Moreover, deficiencies may be associated with reduced NK cell numbers or rather impair specific NK cell effector functions. In recent years, genetic defects underlying the various NK cell deficiencies have been uncovered and have triggered investigative efforts to decipher the molecular mechanisms underlying these disorders. Here we review the associations between inherited human diseases and NK cell development as well as function, with a particular focus on defects in NK cell exocytosis and cytotoxicity. Furthermore we outline how reports of diverse genetic defects have shaped our understanding of NK cell biology.
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Affiliation(s)
- Matthias Voss
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Yenan T Bryceson
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden; Broegelmann Research Laboratory, Institute of Clinical Sciences, University of Bergen, Bergen, Norway.
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70
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Mutational Analysis of the TYR and OCA2 Genes in Four Chinese Families with Oculocutaneous Albinism. PLoS One 2015; 10:e0125651. [PMID: 25919014 PMCID: PMC4412409 DOI: 10.1371/journal.pone.0125651] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 03/17/2015] [Indexed: 11/19/2022] Open
Abstract
Background Oculocutaneous albinism (OCA) is an autosomal recessive disorder. The most common type OCA1 and OCA2 are caused by homozygous or compound heterozygous mutations in the tyrosinase gene (TYR) and OCA2 gene, respectively. Objective The purpose of this study was to evaluate the molecular basis of oculocutaneous albinism in four Chinese families. Patients and Methods Four non-consanguineous OCA families were included in the study. The TYR and OCA2 genes of all individuals were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database. Results Four patients with a diagnosis of oculocutaneous albinism, presented with milky skin, white or light brown hair and nystagmus. Genetic analyses demonstrated that patient A was compound heterozygous for c.1037-7T.A, c.1037-10_11delTT and c.1114delG mutations in the TYR gene; patient B was heterozygous for c.593C>T and c.1426A>G mutations in the OCA2 gene, patients C and D were compound heterozygous mutations in the TYR gene (c.549_550delGT and c.896G>A, c.832C>T and c.985T>C, respectively). The heterozygous c.549_550delGT and c.1114delG alleles in the TYR gene were two novel mutations. Interestingly, heterozygous members in these pedigrees who carried c.1114delG mutations in the TYR gene or c.1426A>G mutations in the OCA2 gene presented with blond or brown hair and pale skin, but no ocular disorders when they were born; the skin of these patients accumulated pigment over time and with sun exposure. Conclusion This study expands the mutation spectrum of oculocutaneous albinism. It is the first time, to the best of our knowledge, to report that c.549_550delGT and c.1114delG mutations in the TYR gene were associated with OCA. The two mutations (c.1114delG in the TYR gene and c.1426A>G in the OCA2 gene) may be responsible for partial clinical manifestations of OCA.
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71
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Yamaoka M, Ishizaki T, Kimura T. Interplay between Rab27a effectors in pancreatic β-cells. World J Diabetes 2015; 6:508-516. [PMID: 25897360 PMCID: PMC4398906 DOI: 10.4239/wjd.v6.i3.508] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/24/2014] [Accepted: 02/09/2015] [Indexed: 02/05/2023] Open
Abstract
The small GTPase Rab27a is a member of the Rab family that is involved in membrane trafficking in various kinds of cells. Rab27a has GTP- and GDP-bound forms, and their interconversion regulates intracellular signaling pathways. Typically, only a GTP-bound GTPase binds its specific effectors with the resulting downstream signals controlling specific cellular functions. We previously identified novel Rab27a-interacting proteins. Surprisingly, some of these proteins interacted with GDP-bound Rab27a. The present study reviews recent progress in our understanding of the roles of Rab27a and its effectors in the secretory process. In pancreatic β-cells, GTP-bound Rab27a regulates insulin secretion at the pre-exocytotic stages via its GTP-specific effectors such as Exophilin8/Slac2-c/MyRIP and Slp4/Granuphilin. Glucose stimulation causes insulin exocytosis. Glucose stimulation also converts Rab27a from its GTP- to its GDP-bound form. GDP-bound Rab27a interacts with GDP-specific effectors and controls endocytosis of the secretory membrane. Thus, Rab27a cycling between GTP- and GDP-bound forms synchronizes with the recycling of secretory membrane to re-use the membrane and keep the β-cell volume constant.
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72
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Sui WH, Huang SH, Wang J, Chen Q, Liu T, Chen ZY. Myosin Va mediates BDNF-induced postendocytic recycling of full-length TrkB and its translocation into dendritic spines. J Cell Sci 2015; 128:1108-22. [PMID: 25632160 DOI: 10.1242/jcs.160259] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival, neurite outgrowth and synaptic plasticity by activating the receptor tropomyosin receptor kinase B (TrkB, also known as NTRK2). TrkB has been shown to undergo recycling after BDNF stimulation. We have previously reported that full-length TrkB (TrkB-FL) are recycled through a Rab11-dependent pathway upon BDNF stimuli, which is important for the translocation of TrkB-FL into dendritic spines and for the maintenance of prolonged BDNF downstream signaling during long-term potentiation (LTP). However, the identity of the motor protein that mediates the local transfer of recycled TrkB-FL back to the plasma membrane remains unclear. Here, we report that the F-actin-based motor protein myosin Va (Myo5a) mediates the postendocytic recycling of TrkB-FL. Blocking the interaction between Rab11 and Myo5a by use of a TAT-tagged peptide consisting of amino acids 55-66 of the Myo5a ExonE domain weakened the association between TrkB-FL and Myo5a and thus impaired TrkB-FL recycling and BDNF-induced TrkB-FL translocation into dendritic spines. Finally, inhibiting Myo5a-mediated TrkB-FL recycling led to a significant reduction in prolonged BDNF downstream signaling. Taken together, these results show that Myo5a mediates BDNF-dependent TrkB-FL recycling and contributes to BDNF-induced TrkB spine translocation and prolonged downstream signaling.
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Affiliation(s)
- Wen-Hai Sui
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Shu-Hong Huang
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Jue Wang
- Central Research Laboratory, The Second Hospital of Shandong University, No.247 Beiyuan Dajie, Jinan, Shandong 250033, P.R. China
| | - Qun Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Ting Liu
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Zhe-Yu Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
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73
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Liu L, Mellerio JE, Martinez AE, McMillan JR, Aristodemou S, Parsons M, McGrath JA. Mutations in EXPH5 result in autosomal recessive inherited skin fragility. Br J Dermatol 2015; 170:196-9. [PMID: 24443915 DOI: 10.1111/bjd.12723] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2013] [Indexed: 12/15/2022]
Abstract
Several different genes have been implicated in the pathophysiology of inherited blistering skin diseases. Recently, autosomal recessive loss-of-function mutations in EXPH5 (encoding exophilin-5, also known as Slac2-b, a protein involved in intracellular vesicle transport) were identified in a new mechanobullous disease resembling a form of epidermolysis bullosa simplex (EBS). Here, we searched for mutations in EXPH5 in a 4-year-old white boy with EBS in whom initial Sanger sequencing of known genes implicated in intraepidermal skin fragility failed to identify pathogenic mutations. Transmission electron microscopy of rubbed nonlesional patient skin revealed disruption of keratinocytes in the lower epidermis with cytolysis and acantholysis, keratin filament clumping and prominent perinuclear cytoplasmic vesicles, and provided the clue to the candidate gene pathology. Sanger sequencing of genomic DNA showed compound heterozygosity for two new mutations in EXPH5, c.1947dupC (p.Pro649fsPro*11) and c.2249C>A (p.Ser750*). Immunofluorescence microscopy of patient skin showed a complete absence of exophilin-5 labelling. This case represents the third pedigree with EXPH5 mutations resulting in inherited skin fragility. The clinical and molecular data expand genotype-phenotype correlation in this new form of EBS and demonstrate the important role of exophilin-5 in keratinocyte cell biology.
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Affiliation(s)
- L Liu
- The Robin Eady National Diagnostic Epidermolysis Bullosa Laboratory, GSTS Pathology, St Thomas' Hospital, London, U.K
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74
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Souza CCR, Dombroski TCD, Machado HR, Oliveira RS, Rocha LB, Rodrigues ARA, Neder L, Chimelli L, Corrêa VMA, Larson RE, Martins AR. Myosin Va is developmentally regulated and expressed in the human cerebellum from birth to old age. Braz J Med Biol Res 2015; 46:164-70. [PMID: 23558932 PMCID: PMC3854355 DOI: 10.1590/1414-431x20122627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 12/03/2012] [Indexed: 12/04/2022] Open
Abstract
Myosin Va functions as a processive, actin-based motor molecule highly enriched
in the nervous system, which transports and/or tethers organelles, vesicles, and
mRNA and protein translation machinery. Mutation of myosin Va leads to Griscelli
disease that is associated with severe neurological deficits and a short life
span. Despite playing a critical role in development, the expression of myosin
Va in the central nervous system throughout the human life span has not been
reported. To address this issue, the cerebellar expression of myosin Va from
newborns to elderly humans was studied by immunohistochemistry using an
affinity-purified anti-myosin Va antibody. Myosin Va was expressed at all ages
from the 10th postnatal day to the 98th year of life, in molecular, Purkinje and
granular cerebellar layers. Cerebellar myosin Va expression did not differ
essentially in localization or intensity from childhood to old age, except
during the postnatal developmental period. Structures resembling granules and
climbing fibers in Purkinje cells were deeply stained. In dentate neurons, long
processes were deeply stained by anti-myosin Va, as were punctate nuclear
structures. During the first postnatal year, myosin Va was differentially
expressed in the external granular layer (EGL). In the EGL, proliferating
prospective granule cells were not stained by anti-myosin Va antibody. In
contrast, premigratory granule cells in the EGL stained moderately. Granule
cells exhibiting a migratory profile in the molecular layer were also moderately
stained. In conclusion, neuronal myosin Va is developmentally regulated, and
appears to be required for cerebellar function from early postnatal life to
senescence.
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Affiliation(s)
- C C R Souza
- Departamento de Neurologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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75
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Jindal R, Shirazi N. A 15-year-old boy with silvery white hair, hepatosplenomegaly, and pancytopenia. Int J Dermatol 2014; 54:393-5. [PMID: 25521170 DOI: 10.1111/ijd.12696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rashmi Jindal
- Department of Dermatology, Venereology and Leprosy, Himalayan Institute of Medical Sciences, Dehradun, India
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76
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Yılmaz M, Çağdaş D, Grandin V, Altıntaş DU, Tezcan İ, de Saint Basile G, Sanal Ö. Griscelli syndrome type 3-like phenotype with MYO-5A exon-F deletion. Pediatr Allergy Immunol 2014; 25:817-9. [PMID: 25283056 DOI: 10.1111/pai.12285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mustafa Yılmaz
- Division of Pediatric Allergy and Immunology, Cukurova University, Adana, Turkey
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77
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Binstock M, Hafeez F, Metchnikoff C, Arron S. Single‐nucleotide polymorphisms in pigment genes and nonmelanoma skin cancer predisposition: a systematic review. Br J Dermatol 2014; 171:713-21. [DOI: 10.1111/bjd.13283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2014] [Indexed: 12/20/2022]
Affiliation(s)
- M. Binstock
- Department of Dermatology University of California San Francisco San Francisco CA 94115 U.S.A
| | - F. Hafeez
- Department of Dermatology University of California San Francisco San Francisco CA 94115 U.S.A
| | - C. Metchnikoff
- Department of Dermatology University of California San Francisco San Francisco CA 94115 U.S.A
| | - S.T. Arron
- Department of Dermatology University of California San Francisco San Francisco CA 94115 U.S.A
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78
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Myosin Vb mediated plasma membrane homeostasis regulates peridermal cell size and maintains tissue homeostasis in the zebrafish epidermis. PLoS Genet 2014; 10:e1004614. [PMID: 25233349 PMCID: PMC4169241 DOI: 10.1371/journal.pgen.1004614] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 07/18/2014] [Indexed: 12/31/2022] Open
Abstract
The epidermis is a stratified epithelium, which forms a barrier to maintain the internal milieu in metazoans. Being the outermost tissue, growth of the epidermis has to be strictly coordinated with the growth of the embryo. The key parameters that determine tissue growth are cell number and cell size. So far, it has remained unclear how the size of epidermal cells is maintained and whether it contributes towards epidermal homeostasis. We have used genetic analysis in combination with cellular imaging to show that zebrafish goosepimples/myosin Vb regulates plasma membrane homeostasis and is involved in maintenance of cell size in the periderm, the outermost epidermal layer. The decrease in peridermal cell size in Myosin Vb deficient embryos is compensated by an increase in cell number whereas decrease in cell number results in the expansion of peridermal cells, which requires myosin Vb (myoVb) function. Inhibition of cell proliferation as well as cell size expansion results in increased lethality in larval stages suggesting that this two-way compensatory mechanism is essential for growing larvae. Our analyses unravel the importance of Myosin Vb dependent cell size regulation in epidermal homeostasis and demonstrate that the epidermis has the ability to maintain a dynamic balance between cell size and cell number.
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79
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Ye S, Huang Y, Joshi S, Zhang J, Yang F, Zhang G, Smyth SS, Li Z, Takai Y, Whiteheart SW. Platelet secretion and hemostasis require syntaxin-binding protein STXBP5. J Clin Invest 2014; 124:4517-28. [PMID: 25244094 DOI: 10.1172/jci75572] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 07/24/2014] [Indexed: 01/22/2023] Open
Abstract
Genome-wide association studies (GWAS) have linked genes encoding several soluble NSF attachment protein receptor (SNARE) regulators to cardiovascular disease risk factors. Because these regulatory proteins may directly affect platelet secretion, we used SNARE-containing complexes to affinity purify potential regulators from human platelet extracts. Syntaxin-binding protein 5 (STXBP5; also known as tomosyn-1) was identified by mass spectrometry, and its expression in isolated platelets was confirmed by RT-PCR analysis. Coimmunoprecipitation studies showed that STXBP5 interacts with core secretion machinery complexes, such as syntaxin-11/SNAP23 heterodimers, and fractionation studies suggested that STXBP5 also interacts with the platelet cytoskeleton. Platelets from Stxbp5 KO mice had normal expression of other key secretory components; however, stimulation-dependent secretion from each of the 3 granule types was markedly defective. Secretion defects in STXBP5-deficient platelets were confirmed via lumi-aggregometry and FACS analysis for P-selectin and LAMP-1 exposure. Interestingly, STXBP5-deficient platelets had altered granule cargo levels, despite having normal morphology and granule numbers. Consistent with secretion and cargo deficiencies, Stxbp5 KO mice showed dramatic bleeding in the tail transection model and defective hemostasis in the FeCl3-induced carotid injury model. Transplantation experiments indicated that these defects were due to loss of STXBP5 in BM-derived cells. Our data demonstrate that STXBP5 is required for normal arterial hemostasis, due to its contributions to platelet granule cargo packaging and secretion.
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80
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Thompson RJ, Knisely AS. Microvilli as markers of disordered apical-membrane trafficking and assembly: bowel and liver. Hepatology 2014; 60:34-6. [PMID: 24668851 DOI: 10.1002/hep.27148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/19/2014] [Accepted: 03/22/2014] [Indexed: 01/22/2023]
Affiliation(s)
- Richard J Thompson
- Institute of Liver Studies, Division of Transplantation Immunology and Mucosal Biology, King's College London School of Medicine, London, UK; Institute of Liver Studies, King's College Hospital, London, UK; Paediatric Liver, GI and Nutrition Centre, King's College Hospital, London, UK
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81
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Wei AH, He X, Li W. Hypopigmentation in Hermansky-Pudlak syndrome. J Dermatol 2014; 40:325-9. [PMID: 23668540 DOI: 10.1111/1346-8138.12025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 09/20/2012] [Indexed: 11/28/2022]
Abstract
Hermansky-Pudlak syndrome (HPS) is characterized by oculocutaneous albinism, bleeding tendency, and ceroid deposition which often leads to death in midlife. Currently, nine genes have been identified as causative for HPS in humans. Hypopigmentation is the prominent feature of HPS, attributable to the disrupted biogenesis of melanosome, a member of the lysosome-related organelle (LRO) family. Current understanding of the cargo transporting mechanisms into the melanosomes expands our knowledge of the pathogenesis of hypopigmentation in HPS patients.
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Affiliation(s)
- Ai-Hua Wei
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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82
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Liakath-Ali K, Vancollie VE, Heath E, Smedley DP, Estabel J, Sunter D, Ditommaso T, White JK, Ramirez-Solis R, Smyth I, Steel KP, Watt FM. Novel skin phenotypes revealed by a genome-wide mouse reverse genetic screen. Nat Commun 2014; 5:3540. [PMID: 24721909 PMCID: PMC3996542 DOI: 10.1038/ncomms4540] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/04/2014] [Indexed: 12/19/2022] Open
Abstract
Permanent stop-and-shop large-scale mouse mutant resources provide an excellent platform to decipher tissue phenogenomics. Here we analyse skin from 538 knockout mouse mutants generated by the Sanger Institute Mouse Genetics Project. We optimize immunolabelling of tail epidermal wholemounts to allow systematic annotation of hair follicle, sebaceous gland and interfollicular epidermal abnormalities using ontology terms from the Mammalian Phenotype Ontology. Of the 50 mutants with an epidermal phenotype, 9 map to human genetic conditions with skin abnormalities. Some mutant genes are expressed in the skin, whereas others are not, indicating systemic effects. One phenotype is affected by diet and several are incompletely penetrant. In-depth analysis of three mutants, Krt76, Myo5a (a model of human Griscelli syndrome) and Mysm1, provides validation of the screen. Our study is the first large-scale genome-wide tissue phenotype screen from the International Knockout Mouse Consortium and provides an open access resource for the scientific community. Large-scale efforts are put into the generation of knockout mutant mice for many individual genes. Here, the authors systematically screen skin from 538 mutant mice and identify 50 mutants with epidermal phenotypes, of which 9 are also associated with human skin defects.
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Affiliation(s)
- Kifayathullah Liakath-Ali
- 1] Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK [2] Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK [3] Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Valerie E Vancollie
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Emma Heath
- Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Damian P Smedley
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Jeanne Estabel
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - David Sunter
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Tia Ditommaso
- 1] Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia [2] Present address: Brigham Regenerative Medicine Center, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | - Jacqueline K White
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | | | - Ian Smyth
- Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Karen P Steel
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Fiona M Watt
- Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
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83
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Lehner S, Gähle M, Dierks C, Stelter R, Gerber J, Brehm R, Distl O. Two-exon skipping within MLPH is associated with coat color dilution in rabbits. PLoS One 2013; 8:e84525. [PMID: 24376820 PMCID: PMC3869861 DOI: 10.1371/journal.pone.0084525] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 11/15/2013] [Indexed: 11/19/2022] Open
Abstract
Coat color dilution turns black coat color to blue and red color to cream and is a characteristic in many mammalian species. Matings among Netherland Dwarf, Loh, and Lionhead Dwarf rabbits over two generations gave evidence for a monogenic autosomal recessive inheritance of coat colour dilution. Histological analyses showed non-uniformly distributed, large, agglomerating melanin granules in the hair bulbs of coat color diluted rabbits. We sequenced the cDNA of MLPH in two dilute and one black rabbit for polymorphism detection. In both color diluted rabbits, skipping of exons 3 and 4 was present resulting in altered amino acids at p.QGL[37-39]QWA and a premature stop codon at p.K40*. Sequencing of genomic DNA revealed a c.111-5C>A splice acceptor mutation within the polypyrimidine tract of intron 2 within MLPH. This mutation presumably causes skipping of exons 3 and 4. In 14/15 dilute rabbits, the c.111-5C>A mutation was homozygous and in a further dilute rabbit, heterozygous and in combination with a homozygous frame shift mutation within exon 6 (c.585delG). In conclusion, our results demonstrated a colour dilution associated MLPH splice variant causing a strongly truncated protein (p.Q37QfsX4). An involvement of further MLPH-associated mutations needs further investigations.
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Affiliation(s)
- Stefanie Lehner
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Marion Gähle
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Claudia Dierks
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ricarda Stelter
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
- Clinic for Pets, Reptiles and Pet and Feral Birds, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Jonathan Gerber
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ralph Brehm
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ottmar Distl
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
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84
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Fontanesi L, Scotti E, Allain D, Dall'Olio S. A frameshift mutation in themelanophilingene causes the dilute coat colour in rabbit (Oryctolagus cuniculus) breeds. Anim Genet 2013; 45:248-55. [DOI: 10.1111/age.12104] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2013] [Indexed: 11/29/2022]
Affiliation(s)
- L. Fontanesi
- Division of Animal Sciences; Department of Agricultural and Food Sciences (DISTAL); University of Bologna; Viale Fanin 46 40127 Bologna Italy
- Centre for Genome Biology; University of Bologna; 40126 Bologna Italy
| | - E. Scotti
- Division of Animal Sciences; Department of Agricultural and Food Sciences (DISTAL); University of Bologna; Viale Fanin 46 40127 Bologna Italy
| | - D. Allain
- INRA; UR631; SAGA; CS52627 31326 Castanet Tolosan France
- INRA; UE 1372; GenESI; Le Magneraud; BP52 17700 Surgères France
| | - S. Dall'Olio
- Division of Animal Sciences; Department of Agricultural and Food Sciences (DISTAL); University of Bologna; Viale Fanin 46 40127 Bologna Italy
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85
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Nascimento AFZ, Trindade DM, Tonoli CCC, de Giuseppe PO, Assis LHP, Honorato RV, de Oliveira PSL, Mahajan P, Burgess-Brown NA, von Delft F, Larson RE, Murakami MT. Structural insights into functional overlapping and differentiation among myosin V motors. J Biol Chem 2013; 288:34131-34145. [PMID: 24097982 PMCID: PMC3837155 DOI: 10.1074/jbc.m113.507202] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/27/2013] [Indexed: 11/06/2022] Open
Abstract
Myosin V (MyoV) motors have been implicated in the intracellular transport of diverse cargoes including vesicles, organelles, RNA-protein complexes, and regulatory proteins. Here, we have solved the cargo-binding domain (CBD) structures of the three human MyoV paralogs (Va, Vb, and Vc), revealing subtle structural changes that drive functional differentiation and a novel redox mechanism controlling the CBD dimerization process, which is unique for the MyoVc subclass. Moreover, the cargo- and motor-binding sites were structurally assigned, indicating the conservation of residues involved in the recognition of adaptors for peroxisome transport and providing high resolution insights into motor domain inhibition by CBD. These results contribute to understanding the structural requirements for cargo transport, autoinhibition, and regulatory mechanisms in myosin V motors.
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Affiliation(s)
- Andrey F Z Nascimento
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Daniel M Trindade
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Celisa C C Tonoli
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Priscila O de Giuseppe
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Leandro H P Assis
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Rodrigo V Honorato
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Paulo S L de Oliveira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Pravin Mahajan
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | | | - Frank von Delft
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Roy E Larson
- Department of Cellular & Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Mario T Murakami
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil.
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86
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Abstract
Specific recognition of the cargo that molecular motors transport or tether to cytoskeleton tracks allows them to perform precise cellular functions at particular times and positions in cells. However, very little is known about how evolution has favored conservation of functions for some isoforms, while also allowing for the generation of new recognition sites and specialized cellular functions. Here we present several crystal structures of the myosin Va or the myosin Vb globular tail domain (GTD) that gives insights into how the motor is linked to the recycling membrane compartments via Rab11 or to the melanosome membrane via recognition of the melanophilin adaptor that binds to Rab27a. The structures illustrate how the Rab11-binding site has been conserved during evolution and how divergence at another site of the GTD allows more specific interactions such as the specific recognition of melanophilin by the myosin Va isoform. With atomic structural insights, these structures also show how either the partner or the GTD structural plasticity upon association is critical for selective recruitment of the motor.
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87
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Dotta L, Parolini S, Prandini A, Tabellini G, Antolini M, Kingsmore SF, Badolato R. Clinical, laboratory and molecular signs of immunodeficiency in patients with partial oculo-cutaneous albinism. Orphanet J Rare Dis 2013; 8:168. [PMID: 24134793 PMCID: PMC3856608 DOI: 10.1186/1750-1172-8-168] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 10/11/2013] [Indexed: 01/04/2023] Open
Abstract
Hypopigmentation disorders that are associated with immunodeficiency feature both partial albinism of hair, skin and eyes together with leukocyte defects. These disorders include Chediak Higashi (CHS), Griscelli (GS), Hermansky-Pudlak (HPS) and MAPBP-interacting protein deficiency syndromes. These are heterogeneous autosomal recessive conditions in which the causal genes encode proteins with specific roles in the biogenesis, function and trafficking of secretory lysosomes. In certain specialized cells, these organelles serve as a storage compartment. Impaired secretion of specific effector proteins from that intracellular compartment affects biological activities. In particular, these intracellular granules are essential constituents of melanocytes, platelets, granulocytes, cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Thus, abnormalities affect pigmentation, primary hemostasis, blood cell counts and lymphocyte cytotoxic activity against microbial pathogens. Among eight genetically distinct types of HPS, only type 2 is characterized by immunodeficiency. Recently, a new subtype, HPS9, was defined in patients presenting with immunodeficiency and oculocutaneous albinism, associated with mutations in the pallidin-encoding gene, PLDN.Hypopigmentation together with recurrent childhood bacterial or viral infections suggests syndromic albinism. T and NK cell cytotoxicity are generally impaired in patients with these disorders. Specific clinical and biochemical phenotypes can allow differential diagnoses among these disorders before molecular testing. Ocular symptoms, including nystagmus, that are usually evident at birth, are common in patients with HPS2 or CHS. Albinism with short stature is unique to MAPBP-interacting protein (MAPBPIP) deficiency, while hemophagocytic lymphohistiocytosis (HLH) mainly suggests a diagnosis of CHS or GS type 2 (GS2). Neurological disease is a long-term complication of CHS, but is uncommon in other syndromic albinism. Chronic neutropenia is a feature of HPS2 and MAPBPIP-deficiency syndrome, whereas it is usually transient in CHS and GS2. In every patient, an accurate diagnosis is required for prompt and appropriate treatment, particularly in patients who develop HLH or in whom bone marrow transplant is required. This review describes the molecular and pathogenetic mechanisms of these diseases, focusing on clinical and biochemical aspects that allow early differential diagnosis.
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Affiliation(s)
- Laura Dotta
- Department of Experimental and Clinical Sciences, Institute of Molecular Medicine “Angelo Nocivelli”, University of Brescia, Brescia, Italy
| | - Silvia Parolini
- Department of Molecular and Translational Medicine, University of Brescia, Brescia 25123, Italy
| | - Alberto Prandini
- Department of Experimental and Clinical Sciences, Institute of Molecular Medicine “Angelo Nocivelli”, University of Brescia, Brescia, Italy
| | - Giovanna Tabellini
- Department of Molecular and Translational Medicine, University of Brescia, Brescia 25123, Italy
| | - Maddalena Antolini
- Department of Experimental and Clinical Sciences, Institute of Molecular Medicine “Angelo Nocivelli”, University of Brescia, Brescia, Italy
| | - Stephen F Kingsmore
- Center for Pediatric Genomic Medicine, Children’s Mercy Hospital, Kansas City, MO 64108, USA
| | - Raffaele Badolato
- Department of Experimental and Clinical Sciences, Institute of Molecular Medicine “Angelo Nocivelli”, University of Brescia, Brescia, Italy
- Istituto di Medicina Molecolare “Angelo Nocivelli”, Universita' di Brescia, c/o Spedali Civili, Brescia 25123, Italy
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88
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Hamidieh AA, Pourpak Z, Yari K, Fazlollahi MR, Hashemi S, Behfar M, Moin M, Ghavamzadeh A. Hematopoietic stem cell transplantation with a reduced-intensity conditioning regimen in pediatric patients with Griscelli syndrome type 2. Pediatr Transplant 2013; 17:487-91. [PMID: 23714271 DOI: 10.1111/petr.12092] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/15/2013] [Indexed: 12/27/2022]
Abstract
Partial albinism with variable immunodeficiency are the two major characteristics of Griscelli syndrome type 2 (GS-2). This syndrome is usually associated with a high mortality rate and commonly results in early childhood death. Patients suffer from different infections and experience crisis of HLH. HSCT remains the sole curative treatment for GS-2. We prospectively analyzed the outcomes of transplantation with RIC regimen in five patients. The median age at transplantation was 21.6 months (range: 12-30). All of the patients underwent HSCT from HLA-matched related donors. Currently, four patients are cured, and symptoms of recurrent infections and HLH crisis are not seen in them. The only patient who died had undergone HSCT in the accelerated phase of HLH. One patient who developed acute GvHD had a favorable response to therapy. No chronic GvHD occurred in patients. It seems that the use of RIC regimen as a method of transplant preparation is effective and tolerable in this group of patients with various comorbidities. It is recommended to carry out HSCT in these patients at lower ages, before presentations of different infections and HLH crisis.
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Affiliation(s)
- Amir Ali Hamidieh
- Hematology-Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran
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89
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Abstract
Class V myosins (MyoV), the most studied unconventional myosins, recognize numerous cargos mainly via the motor's globular tail domain (GTD). Little is known regarding how MyoV-GTD recognizes such a diverse array of cargos specifically. Here, we solved the crystal structures of MyoVa-GTD in its apo-form and in complex with two distinct cargos, melanophilin and Rab interacting lysosomal protein-like 2. The apo-MyoVa-GTD structure indicates that most mutations found in patients with Griscelli syndrome, microvillus inclusion disease, or cancers or in "dilute" rodents likely impair the folding of GTD. The MyoVa-GTD/cargo complex structure reveals two distinct cargo-binding surfaces, one primarily via charge-charge interaction and the other mainly via hydrophobic interactions. Structural and biochemical analysis reveal the specific cargo-binding specificities of various isoforms of mammalian MyoV as well as very different cargo recognition mechanisms of MyoV between yeast and higher eukaryotes. The MyoVa-GTD structures resolved here provide a framework for future functional studies of vertebrate class V myosins.
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90
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Abstract
Intracellular membrane trafficking requires the complex interplay of several classes of trafficking proteins. Rab proteins, the largest subfamily of the Ras superfamily of small G-proteins, are central regulators of all aspects of intracellular trafficking processes including vesicle budding and uncoating, motility, tethering and fusion. In the present paper, we discuss the discovery, evolution and characterization of the Rab GTPase family. We examine their basic functional roles, their important structural features and the regulatory proteins which mediate Rab function. We speculate on outstanding issues in the field, such as the mechanisms of Rab membrane association and the co-ordinated interplay between distinct Rab proteins. Finally, we summarize the data implicating Rab proteins in an ever increasing number of diseases.
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91
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Seixas E, Barros M, Seabra MC, Barral DC. Rab and Arf proteins in genetic diseases. Traffic 2013; 14:871-85. [PMID: 23565987 DOI: 10.1111/tra.12072] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/29/2023]
Abstract
Rab and ADP-ribosylation factor (Arf) family proteins are master regulators of membrane trafficking and are involved in all steps of vesicular transport. These families of small guanine-nucleotide-binding (G) proteins are well suited to regulate membrane trafficking processes since their nucleotide state determines their conformation and the capacity to bind to a multitude of effectors, which mediate their functions. In recent years, several inherited diseases have been associated with mutations in genes encoding proteins belonging to these two families or in proteins that regulate their GTP-binding cycle. The genetic diseases that are caused by defects in Rabs, Arfs or their regulatory proteins are heterogeneous and display diverse symptoms. However, these diseases mainly affect two types of subcellular compartments, namely lysosome-related organelles and cilia. Also, several of these diseases affect the nervous system. Thus, the study of these diseases represents an opportunity to understand their etiology and the molecular mechanisms involved, as well as to develop novel therapeutic strategies.
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Affiliation(s)
- Elsa Seixas
- CEDOC, Faculdade de Ciências Médicas, FCM, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
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92
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Myosin motors at neuronal synapses: drivers of membrane transport and actin dynamics. Nat Rev Neurosci 2013; 14:233-47. [DOI: 10.1038/nrn3445] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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93
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Myosin-V is activated by binding secretory cargo and released in coordination with Rab/exocyst function. Dev Cell 2013; 23:769-81. [PMID: 23079598 DOI: 10.1016/j.devcel.2012.09.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 06/01/2012] [Accepted: 09/05/2012] [Indexed: 02/01/2023]
Abstract
Cell organization requires motor-dependent transport of specific cargos along cytoskeletal elements. How the delivery cycle is coordinated with other events is poorly understood. Here we define the in vivo delivery cycle of myosin-V in its essential function of secretory vesicle transport along actin cables in yeast. We show that myosin-V is activated by binding a secretory vesicle and that myosin-V mutations that compromise vesicle binding render the motor constitutively active. About ten motors associate with each secretory vesicle for rapid transport to sites of cell growth. Once transported, the motors remain associated with the secretory vesicles until they undergo exocytosis. Motor release is temporally regulated by vesicle-bound Rab-GTP hydrolysis and requires vesicle tethering by the exocyst complex but does not require vesicle fusion with the plasma membrane. All components of this transport cycle are conserved in vertebrates, so these results should be generally applicable to other myosin-V delivery cycles.
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94
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Harper MT, van den Bosch MTJ, Hers I, Poole AW. Absence of platelet phenotype in mice lacking the motor protein myosin Va. PLoS One 2013; 8:e53239. [PMID: 23349704 PMCID: PMC3548825 DOI: 10.1371/journal.pone.0053239] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 11/27/2012] [Indexed: 12/22/2022] Open
Abstract
Background The motor protein myosin Va plays an important role in the trafficking of intracellular vesicles. Mutation of the Myo5a gene causes Griscelli syndrome type 1 in humans and the dilute phenotype in mice, which are both characterised by pigment dilution and neurological defects as a result of impaired vesicle transport in melanocytes and neuroendocrine cells. The role of myosin Va in platelets is currently unknown. Rab27 has been shown to be associated with myosin Va cargo vesicles and is known to be important in platelet dense granule biogenesis and secretion, a crucial event in thrombus formation. Therefore, we hypothesised that myosin Va may regulate granule secretion or formation in platelets. Methodology/Principal Findings Platelet function was studied in vitro using a novel Myo5a gene deletion mouse model. Myo5a−/− platelets were devoid of myosin Va, as determined by immunoblotting, and exhibited normal expression of surface markers. We assessed dense granule, α-granule and lysosomal secretion, integrin αIIbβ3 activation, Ca2+ signalling, and spreading on fibrinogen in response to collagen-related peptide or the PAR4 agonist, AYPGKF in washed mouse platelets lacking myosin Va or wild-type platelets. Surprisingly, Myo5a−/− platelets showed no significant functional defects in these responses, or in the numbers of dense and α-granules expressed. Conclusion Despite the importance of myosin Va in vesicle transport in other cells, our data demonstrate this motor protein has no non-redundant role in the secretion of dense and α-granules or other functional responses in platelets.
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Affiliation(s)
- Matthew T. Harper
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | | | - Ingeborg Hers
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Alastair W. Poole
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
- * E-mail:
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95
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Abstract
Directed transport of the mRNA binding protein, zipcode binding protein1 (ZBP1), into developing axons is believed to play an important role in mRNA localization and local protein synthesis. The role of molecular motors in this process is unclear. We elucidated a role for myosin Va (MyoVa) to modulate the axonal localization and transport of ZBP1 in axons. Using cultured rat hippocampal neurons, ZBP1 colocalized with MyoVa in axons and growth cones. Interaction of MyoVa with ZBP1 was evident by coimmunoprecipitation of endogenous and overexpressed proteins. Inhibition of MyoVa function with the globular tail domain (GTD) of MyoVa protein or short hairpin RNA led to an accumulation of ZBP1 in axons. Live cell imaging of mCherryZBP1 in neurons expressing GTD showed an increase in the number of motile particles, run length, and stimulated anterograde moving ZBP1 particles, suggesting that MyoVa controls availability of ZBP1 for microtubule-dependent transport. These findings suggest a novel regulatory role for MyoVa in the transport of ZBP1 within axons.
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96
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Abstract
The progress of molecular genetics helps clinicians to prove or exclude a suspected diagnosis for a vast and yet increasing number of genodermatoses. This leads to precise genetic counselling, prenatal diagnosis and preimplantation genetic haplotyping for many inherited skin conditions. It is also helpful in such occasions as phenocopy, late onset and incomplete penetrance, uniparental disomy, mitochondrial inheritance and pigmentary mosaicism. Molecular methods of two genodermatoses are explained in detail, i.e. genodermatoses with skin fragility and neurofibromatosis type 1.
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Affiliation(s)
- Vesarat Wessagowit
- Molecular Genetics Laboratory, The Institute of Dermatology, Bangkok, Thailand.
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97
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Wei AH, Li W. Hermansky-Pudlak syndrome: pigmentary and non-pigmentary defects and their pathogenesis. Pigment Cell Melanoma Res 2012; 26:176-92. [DOI: 10.1111/pcmr.12051] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Affiliation(s)
| | - Wei Li
- State Key Laboratory of Molecular Developmental Biology; Institute of Genetics & Developmental Biology; Chinese Academy of Sciences; Beijing; China
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98
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Germline Mutation in EXPH5 Implicates the Rab27B Effector Protein Slac2-b in Inherited Skin Fragility. Am J Hum Genet 2012. [PMID: 23176819 DOI: 10.1016/j.ajhg.2012.10.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Rab GTPase Rab27B and one of its effector proteins, Slac2-b (also known as EXPH5, exophilin-5), have putative roles in intracellular vesicle trafficking but their relevance to human disease is not known. By using whole-exome sequencing, we identified a homozygous frameshift mutation in EXPH5 in three siblings with inherited skin fragility born to consanguineous Iraqi parents. All three individuals harbor the mutation c.5786delC (p.Pro1929Leufs(∗)8) in EXPH5, which truncates the 1,989 amino acid Slac2-b protein by 52 residues. The clinical features comprised generalized scale-crusts and occasional blisters, mostly induced by trauma, as well as mild diffuse pigmentary mottling on the trunk and proximal limbs. There was no increased bleeding tendency, no neurologic abnormalities, and no increased incidence of infection. Analysis of an affected person's skin showed loss of Slac2-b immunostaining (C-terminal antibody), disruption of keratinocyte adhesion within the lower epidermis, and an increased number of perinuclear vesicles. A role for Slac2-b in keratinocyte biology was supported by findings of cytoskeletal disruption (mainly keratin intermediate filaments) and decreased keratinocyte adhesion in both keratinocytes from an affected subject and after shRNA knockdown of Slac2-b in normal keratinocytes. Slac2-b was also shown to colocalize with Rab27B and β4 integrin to early adhesion initiation sites in spreading normal keratinocytes. Collectively, our findings identify an unexpected role for Slac2-b in inherited skin fragility and expand the clinical spectrum of human disorders of GTPase effector proteins.
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99
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Abstract
Griscelli syndrome (GS) is a rare autosomal recessive disorder associated with skin or hair hypopigmentation, hepatosplenomegaly, pancytopenia, and immunologic and central nervous system abnormalities. GS type II is caused by RAB27A mutations. We present RAB27A mutation analysis of 6 cases diagnosed as GS type II. Missense mutations (L26P and L130P) in 2 cases, deletion of 5 bases (514delCAAGC) in 2 cases, and 1 base deletion (148delA) in 2 cases were detected. This report has importance in phenotype-genotype correlation of different types of mutations including missense mutations and deletions within the RAB27A gene in GSII syndrome.
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100
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Sitaram A, Marks MS. Mechanisms of protein delivery to melanosomes in pigment cells. Physiology (Bethesda) 2012; 27:85-99. [PMID: 22505665 DOI: 10.1152/physiol.00043.2011] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vertebrate pigment cells in the eye and skin are useful models for cell types that use specialized endosomal trafficking pathways to partition cargo proteins to unique lysosome-related organelles such as melanosomes. This review describes current models of protein trafficking required for melanosome biogenesis in mammalian melanocytes.
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Affiliation(s)
- Anand Sitaram
- Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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