Probably involved in vesicular trafficking via its association with the CART complex. The CART complex is necessary for efficient transferrin receptor recycling but not for EGFR degradation (By similarity). Positively regulates motility of microtubule-dependent motor protein KIF21B (PubMed:24086586). Associates with myosin-Vb (MYO5B) and alpha-actinin-4 (ACTN4) (By similarity). Component of the CART complex, at least composed of ACTN4, HGS/HRS, MYO5B and TRIM3 (By similarity). Interacts with ZFYVE28/LST2 (By similarity). Interacts with KIF21B (PubMed:24086586). The interaction with MYO5B is dependent upon its NHL repeats, which form a beta-propeller (NHL) domain containing six blades. No visible phenotype. Belongs to the TRIM/RBCC family.