Ligand-binding domain of membrane guanylyl cyclase G
This group includes the ligand-binding domain of membrane guanylyl cyclase G (GC-G) which is a sperm surface receptor and might function, similar to its sea urchin counterpart, in the early signaling event that regulates the Ca2+ influx/efflux and subsequent motility response in sperm. GC-G appears to be a pseudogene in human. Furthermore, in contrast to the other orphan receptor GCs, GC-G has a broad tissue distribution in rat, including lung, intestine, kidney, and skeletal muscle.
Jiyao W et al.(2023). "The conserved domain database in 2023.",