VAMP7 Modulates Ciliary Biogenesis in Kidney Cells
Epithelial cells elaborate specialized domains with distinguishable compositions of lipid as well as protein, which include the basolateral and apical surfaces together with primary cilia. For proper functioning of the cell, maintenance of these domains; identity is necessary and requires the selective and efficient SNARE-mediated vesicles fusion that contain newly produced and recycling proteins that have the suitable target membrane. There exist many pathways to carry freshly synthesized proteins to the kidney cells’ apical surface, and the post-Golgi SNAREs, or VAMPs that participate in these distinguishable pathways have not been discovered. There has been implication of VAMP7 in delivery of apical protein in other types of cell. This study was aimed at investigating whether VAMP7 serves in any of the several pathways of delivery to the MDCK cells’ apical surface.
VAMP7 showed in polarized Madin Darby canine kidney cells co-localized basically with positive compartments of LAMP2, as well as knockdown mediated by siRNA regulated lysosome size, which was consistent with the known VAMP7function in delivery of lysosomes. VAMP7 knockdown, however, showed no effect on numerous cargoes’ apical delivery examined, but reduced the primary cilia’s frequency and length. In addition, VAMP7 knockdown interrupted cystogenesis in cells that were grown in a membrane matrix that had a three dimensional basement.
The effects of depletion of VAMP7 on cystogenesis and ciliogenesis were not directly associated with the interruption of lysosomal function since cyst morphology and cilia lengths were not affected in a model of MDCK lysosomal storage disorder. The current data proposed that VAMP7 serves an important role in formation of lumen, as well as ciliogenesis. This was the first research that implicated an R-SNARE in cystogenesis and ciliogenesis. Further studies are needed to ascertain the steps in ciliogenesis that need VAMP7.
