The function of CLVS1 (clavesin 1, ENSG00000177182) is as follows. Required for normal morphology of late endosomes and/or lysosomes in neurons (By similarity). Binds phosphatidylinositol 3,5- bisphosphate (PtdIns(3,5)P2). {ECO:0000250, ECO:0000269|PubMed:19651769}.