Acts as component of the retromer cargo-selective complex (CSC) (PubMed:21040701, PubMed:21920005). The CSC is believed to be the core functional component of retromer or respective retromer complex variants acting to prevent missorting of selected transmembrane cargo proteins into the lysosomal degradation pathway. The recruitment of the CSC to the endosomal membrane involves RAB7A and SNX3. The SNX-BAR retromer mediates retrograde transport of cargo proteins from endosomes to the trans-Golgi network (TGN) and is involved in endosome-to-plasma membrane transport for cargo protein recycling. The SNX3-retromer mediates the retrograde transport of WLS distinct from the SNX-BAR retromer pathway. The SNX27-retromer is believed to be involved in endosome-to-plasma membrane trafficking and recycling of a broad spectrum of cargo proteins. The CSC seems to act as recruitment hub for other proteins, such as the WASH complex and TBC1D5 (By similarity). May be involved in retrograde transport of SORT1 but not of IGF2R (PubMed:21040701). Acts redundantly with VSP26A in SNX-27 mediated endocytic recycling of SLC2A1/GLUT1 (PubMed:25136126). Component of the heterotrimeric retromer cargo-selective complex (CSC), also described as vacuolar protein sorting subcomplex (VPS), formed by VPS26 (VPS26A or VPS26B), VPS29 and VPS35 (PubMed:21040701, PubMed:21920005, PubMed:18088321, PubMed:20875039). The CSC has a highly elongated structure with VPS26 and VPS29 binding independently at opposite distal ends of VPS35 as central platform (Probable). The CSC is believed to associate with variable sorting nexins to form functionally distinct retromer complex variants. The originally described SNX-BAR retromer is a pentamer containing the CSC and a heterodimeric membrane-deforming subcomplex formed between SNX1 or SNX2 and SNX5 or SNX6 (also called SNX-BAR subcomplex); the respective CSC and SNX-BAR subcomplexes associate with low affinity. The CSC associates with SNX3 to form a SNX3-retromer complex. The CSC associates with SNX27, the WASH complex and the SNX-BAR subcomplex to form the SNX27-retromer complex (By similarity). Interacts with VPS29, VPS35, TBC1D5, GOLPH3, SNX27 (PubMed:16190980, PubMed:21040701, PubMed:21920005, PubMed:25136126). Endosomal localization is reported controversially. Does not localize to endosomes (PubMed:16190980). Localizes to early and late endosomal structures (PubMed:21920005, PubMed:18088321). Ubiquitously expressed in developing embryo and adult. Highly expressed in brain. Belongs to the VPS26 family.