FYVE-related domain found in Slp homolog lacking C2 domains a (SlaC2-a) and similar proteins
SlaC2-a, also termed melanophilin, or exophilin-3, is a GTP-bound form of Rab27A-, myosin Va-, and actin-binding protein present on melanosomes. It is involved in the control of transferring of melanosomes from microtubules to actin filaments. It also functions as a melanocyte type myosin Va (McM5) binding partner and directly activates the actin-activated ATPase activity of McM5 through forming a tripartite protein complex with Rab27A and an actin-based motor myosin Va. SlaC2-a belongs to the Slp homolog lacking C2 domains (Slac2) family. It contains an N-terminal Slp homology domain (SHD), but lacks tandem C2 domains. The SHD consists of two conserved regions, designated SHD1 (Slp homology domain 1) and SHD2, which may function as protein interaction sites. The SHD1 and SHD2 of SlaC2-a are separated by a putative FYVE zinc finger, which resembles 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. Moreover, Slac2-a has a middle myosin-binding domain and a C-terminal actin-binding domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",