1
|
Kim JD, Chun AY, Mangan RJ, Brown G, Mourao Pacheco B, Doyle H, Leonard A, El Bejjani R. A conserved retromer-independent function for RAB-6.2 in C. elegans epidermis integrity. J Cell Sci 2019; 132:jcs.223586. [PMID: 30665892 DOI: 10.1242/jcs.223586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 01/09/2019] [Indexed: 12/13/2022] Open
Abstract
Rab proteins are conserved small GTPases that coordinate intracellular trafficking essential to cellular function and homeostasis. RAB-6.2 is a highly conserved C. elegans ortholog of human RAB6 proteins. RAB-6.2 is expressed in most tissues in C. elegans and is known to function in neurons and in the intestine to mediate retrograde trafficking. Here, we show that RAB-6.2 is necessary for cuticle integrity and impermeability in C. elegans RAB-6.2 functions in the epidermis to instruct skin integrity. Significantly, we show that expression of a mouse RAB6A cDNA can rescue defects in C. elegans epidermis caused by lack of RAB-6.2, suggesting functional conservation across phyla. We also show that the novel function of RAB-6.2 in C. elegans cuticle development is distinct from its previously described function in neurons. Exocyst mutants partially phenocopy rab-6.2-null animals, and rab-6.2-null animals phenocopy mutants that have defective surface glycosylation. These results suggest that RAB-6.2 may mediate the trafficking of one or many secreted glycosylated cuticle proteins directly, or might act indirectly by trafficking glycosylation enzymes to their correct intracellular localization.
Collapse
Affiliation(s)
- Jonathan D Kim
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | - Andy Y Chun
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | - Riley J Mangan
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | - George Brown
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | | | - Hannah Doyle
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | - Austin Leonard
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | | |
Collapse
|
2
|
Seifert W, Kühnisch J, Maritzen T, Lommatzsch S, Hennies HC, Bachmann S, Horn D, Haucke V. Cohen syndrome-associated protein COH1 physically and functionally interacts with the small GTPase RAB6 at the Golgi complex and directs neurite outgrowth. J Biol Chem 2014; 290:3349-58. [PMID: 25492866 DOI: 10.1074/jbc.m114.608174] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Postnatal microcephaly, intellectual disability, and progressive retinal dystrophy are major features of autosomal recessive Cohen syndrome, which is caused by mutations in the gene COH1 (VPS13B). We have recently identified COH1 as a Golgi-enriched scaffold protein that contributes to the structural maintenance and function of the Golgi complex. Here, we show that association of COH1 with the Golgi complex depends on the small GTPase RAB6. RNAi-mediated knockdown of RAB6A/A' prevents the localization of COH1 to the Golgi complex. Expression of the constitutively inactive RAB6_T27N mutant led to an increased solubilization of COH1 from lipid membrane preparations. Co-IP experiments confirmed the physical interaction of COH1 with RAB6 that preferentially occurred with the constitutively active RAB6_Q72L mutants. Depletion of COH1 in primary neurons negatively interfered with neurite outgrowth, indicating a causal link between the integrity of the Golgi complex and axonal outgrowth. We conclude that COH1 is a RAB6 effector protein and that reduced brain size in Cohen syndrome patients likely results from impaired COH1 function at the Golgi complex, causing decreased neuritogenesis.
Collapse
Affiliation(s)
- Wenke Seifert
- From the Institute of Vegetative Anatomy, Charité - Universitätsmedizin Berlin, 10115 Berlin, Germany,
| | - Jirko Kühnisch
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany, Max-Planck-Institute for Molecular Genetics, FG Development and Disease, 14195 Berlin, Germany
| | - Tanja Maritzen
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Institute for Molecular Pharmacology, 13125 Berlin, Germany
| | - Stefanie Lommatzsch
- From the Institute of Vegetative Anatomy, Charité - Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Hans Christian Hennies
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany, and the Division of Human Genetics, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Sebastian Bachmann
- From the Institute of Vegetative Anatomy, Charité - Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Denise Horn
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Volker Haucke
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Institute for Molecular Pharmacology, 13125 Berlin, Germany
| |
Collapse
|