guanylyl cyclase activating protein 2; GCAP 2; guanylate cyclase activator 1B (GUCA1B, GCAP2)

Function

• stimulates guanylyl cyclases (GC1 & GC2) when free Ca+2 is low
• inhibits guanylyl cyclases (GC1 & GC2) when free Ca+2 is high
• this Ca+2-sensitive regulation of guanylyl cyclase is a key event in recovery of dark state of rod photoreceptors following light exposure

Structure

contains 4 EF-hand domains

Compartment

• cell membrane
• membranes of rod outer segment

Expression

retina. cones & rod

Pathology

• defects in GUCA1B are the cause of retinitis pigmentosa type 48

Notes

binds 3 Ca+2 (putative)

More general terms

• Ca+2 binding protein
• myristoylated protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=2979
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:2979
• OMIM: https://mirror.omim.org/entry/602275
• OMIM: https://mirror.omim.org/entry/613827
• UniProt: http://www.uniprot.org/uniprot/Q9UMX6.html