This family includes SPRY domain in SSH4 (suppressor of SHR3 null mutation protein 4) and similar proteins. SSH4 is a component of the endosome-vacuole trafficking pathway that regulates nutrient transport and may be involved in processes determining whether plasma membrane proteins are degraded or routed to the plasma membrane. The SPRY domain in SSH4 may be involved in cargo recognition, either directly or by combination with other adaptors, possibly leading to a higher selectivity. In yeast, SSH4 and the homologous protein EAR1 (endosomal adapter of RSP5) recruit Rsp5p, an essential ubiquitin ligase of the Nedd4 family, and assist it in its function at multivesicular bodies by directing the ubiquitylation of specific cargoes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",