FYVE-related domain found in rabphilin-3A, Rab effector Noc2, and similar proteins
This family includes rabphilin-3A and Rab effector Noc2. Rabphilin-3A, also termed exophilin-1, is an effector protein that binds to the GTP-bound form of Rab3A, which is one of the most abundant Rab proteins in neurons and predominantly localized to synaptic vesicles. Rabphilin-3A is homologous to alpha-Rab3-interacting molecules (RIMs). It is a multi-domain protein containing an N-terminal Rab3A effector domain, a proline-rich linker region, and two tandem C2 domains. The effector domain binds specifically to the activated GTP-bound state of Rab3A and harbors a conserved FYVE zinc finger. The C2 domains are responsible for the binding of phosphatidylinositol-4,5-bisphosphate (PIP2) , a key player in the neurotransmitter release process. Thus, Rabphilin-3A has also been implicated in vesicle trafficking. Rab effector Noc2, also termed No C2 domains protein, or rabphilin-3A-like protein (RPH3AL), is a Rab3 effector that mediates the regulation of secretory vesicle exocytosis in neurons and certain endocrine cells. It also functions as a Rab27 effector and is involved in isoproterenol (IPR)-stimulated amylase release from acinar cells. Noc2 contains an N-terminal Rab3A effector domain which only harbors a conserved FYVE zinc finger. The FYVE domains of Rabphilin-3A and Noc2 resemble a FYVE-related domain that is structurally similar to the canonical FYVE domains but lacks the three signature sequences: an N-terminal WxxD motif (x for any residue), the central basic R(R/K)HHCRxCG patch, and a C-terminal RVC motif.
Jiyao W et al.(2023). "The conserved domain database in 2023.",