The BLTP3B protein of 1464 aas and 0 - 2 TMSs. Also called the SHIP164 protein.  BLTP3B or SHIP164 is of 1464 aas and 0 - 2 TMSs. It is a tube-forming lipid transport protein which mediates the transfer of lipids between membranes at organelle contact sites and is required for retrograde trafficing of vesicle clusters in the early endocytic pathway to the Golgi complex (Otto et al. 2010). Cellular membranes differ in protein and lipid compositions as well as in the protein-lipid ratio. Progression of membranous organelles along traffic routes requires mechanisms to control bilayer lipid chemistry and their abundance relative to proteins. Structural and functional characterization of VPS13-family proteins has suggested a mechanism through which lipids can be transferred in bulk from one membrane to another at membrane contact sites, and thus independently of vesicular traffic. Hanna et al. 2022 showed that SHIP164 (UHRF1BP1L) shares structural and lipid transfer properties with these proteins and is localized on a subpopulation of vesicle clusters in the early endocytic pathway whose membrane cargo includes the cation-independent mannose- 6-phosphate receptor (MPR). Loss of SHIP164 disrupts retrograde traffic of these organelles to the Golgi complex. These findings raise the possibility that bulk transfer of lipids to endocytic membranes may play a role in their traffic (Hanna et al. 2022).