Mediates the transfer of lipids between membranes at organelle contact sites (By similarity). Binds phosphatidylinositol 3-phosphate (By similarity). Functions as a tethering factor in the slow endocytic recycling pathway, to assist traffic between early and recycling endosomes ( ). Involved in the transport of proacrosomal vesicles to the nuclear dense lamina (NDL) during spermatid development (By similarity). Plays a role in the assembly of the Golgi apparatus, possibly by mediating trafficking to the Golgi membrane . Plays a role in the development of the nervous system, and may be required for neuron projection development (, ). May also play a role during adipose tissue development . Required for maintenance of the ocular lens (By similarity).
Subcellular locations: Recycling endosome membrane, Cytoplasmic vesicle, Secretory vesicle, Acrosome membrane, Golgi apparatus, Cis-Golgi network membrane, Endoplasmic reticulum-Golgi intermediate compartment membrane, Golgi apparatus, Trans-Golgi network membrane, Early endosome membrane, Lysosome membrane
Localizes to proacrosomal and acrosomal vesicles and not the Golgi apparatus during acrosome formation.
Widely expressed . There is apparent differential expression of different transcripts (, ). In fetal brain, lung, liver, and kidney, two transcripts of 2 and 5 kb are identified . These transcripts are also seen in all adult tissues analyzed . A larger transcript (12-14 kb) is expressed in prostate, testis, ovary, and colon in the adult . Expression is very low in adult brain tissue . Expressed in peripheral blood lymphocytes . Isoform 1 and isoform 2 are expressed in brain and retina (, ). Isoform 2 is expressed ubiquitously (, ).