FYVE-related domain found in the synaptotagmin-like proteins 3, 4, 5
The synaptotagmin-like proteins 1-5 (Slp1-5) family belongs to the carboxyl-terminal-type (C-type) tandem C2 proteins superfamily, which also contains the synaptotagmin and the Doc2 families. Slp proteins are putative membrane trafficking proteins that are characterized by the presence of a unique N-terminal Slp homology domain (SHD), and C-terminal tandem C2 domains (known as the C2A domain and C2B domain). The SHD consists of two conserved regions, designated SHD1 (Slp homology domain 1) and SHD2. The SHD1 and SHD2 of Slp3, Slp4 and Slp5 are separated by a putative FYVE zinc finger. By contrast, Slp1 and Slp2 lack such zinc finger and their SHD1 and SHD2 are linked together. This model corresponds to the FYVE zinc finger. At this point, Slp1 and Slp2 are not included in this model. Moreover, the FYVE domains of Slp3, Slp4 and Slp5 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.