| Primary Identifier | IPR007515 | Type | Family |
| Short Name | Mss4 |
| description | MSS4 (mammalian suppressor of Sec4) is an evolutionarily highly conserved protein, which is expressed in all mammalian tissues. Although it was first proposed to function as a guanine exchange factor (GEF) for Rab GTPases, it was soon described as a quite inefficient GEF and was thus suggested to function rather as a chaperone, protecting nucleotide free Rabs from degradation, than as a GEF [].The structure of MSS4 revealed a mostly beta fold stabilized by a Zn(2+) ion coordinated by cysteine residues from two CxxC motifs. The fold of the MSS4 domain consists of a central beta sheet (betaG-betaK) flanked by a beta hairpin (betaB-betaC) on one side and a small variable sheet on the other. A single Zn(2+) ion, coordinated by the thiol groups of cysteine residues from two CxxC motifs located in the betaB-betaC and betaI-betaJ loops, appears to play an important structural role by reinforcing the hydrophobic core formed by the betaB-betaC hairpin, the betaG-betaH loop, and the central beta sheet [, , ]. |
