May be a guanine exchange factor (GEF) for Rab21, Rab32 and Rab38 and regulate endosome dynamics. May regulate the participation of VAMP7 in membrane fusion events; in vitro inhibits VAMP7-mediated SNARE complex formation by trapping VAMP7 in a closed, fusogenically inactive conformation (By similarity). Involved in peripheral melanosomal distribution of TYRP1 in melanocytes; the function, which probably is implicating vesicle-trafficking, includes cooperation with Rab32, Rab38 and VAMP7. Involved in the regulation of neurite growth; the function seems to require its GEF activity, probably towards Rab21, and VAMP7 but not Rab32/38. Proposed to be involved in Golgi sorting of VAMP7 and transport of VAMP7 vesicles to the cell surface; the function seems to implicate kinesin heavy chain isoform 5 proteins, GOLGA4, RAB21 and MACF1. Required for the colocalization of VAMP7 and Rab21, probably on TGN sites. Involved in GLUT1 endosome-to-plasma membrane trafficking; the function is dependent of association with VPS29. Regulates the proper trafficking of melanogenic enzymes TYR, TYRP1 and DCT/TYRP2 to melanosomes in melanocytes (By similarity). Interacts with RAB21 (GDP-bound form), VPS29, KIF5A, KIF5C, GOLGA4. Interacts with RAB32 (GTP-bound form), RAB38 (GTP-bound form), VAMP7. Interacts with low affinity with RAB5. ANKRD27:RAB32 heterodimers can homodimerize to form tetramers. Can interact with RAB38 or RAB32, VPS29 and VAMP7 simultaneously (By similarity). A decreased interaction with RAB32 seen in the presence of SGSM2 (By similarity). Colocalizes with VAMP7 in transport vesicles in the shaft of hippocampal neurons (By similarity).