Description | Carbonic anhydrase related proteins (CARPs) are sequence similar to carbonic anhydrases. Carbonic anhydrases are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism. CARPs have lost conserved histidines involved in zinc binding and consequently their catalytic activity [ , ]. CARP VIII may play roles in various biological processes of the central nervous system and is associated with motor coordination [, , ]. CARP VIII has been shown to bind inositol 1,4,5-triphosphate (IP3) receptor type I (IP3RI), reducing the affinity of the receptor for IP3. IP3RI is an intracellular IP3-gated Ca2+ channel located on intracellular Ca2+ stores. IP3RI converts IP3 signaling into Ca2+ signaling thereby participating in a variety of cell functions []. CARP VIII has been linked to neurodegeneration and development of colorectal and lung cancers in humans [].Carbonic anhydrases (CA: ) are zinc metalloenzymes which catalyse the reversible hydration of carbon dioxide to bicarbonate [ , ]. CAs have essential roles in facilitating the transport of carbon dioxide and protons in the intracellular space, across biological membranes and in the layers of the extracellular space; they are also involved in many other processes, from respiration and photosynthesis in eukaryotes to cyanate degradation in prokaryotes. There are five known evolutionarily distinct CA families (alpha, beta, gamma, delta and epsilon) that have no significant sequence identity and have structurally distinct overall folds. Some CAs are membrane-bound, while others act in the cytosol; there are several related proteins that lack enzymatic activity. The active site of alpha-CAs is well described, consisting of a zinc ion coordinated through 3 histidine residues and a water molecule/hydroxide ion that acts as a potent nucleophile. The enzyme employs a two-step mechanism: in the first step, there is a nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide; in the second step, the active site is regenerated by the ionisation of the zinc-bound water molecule and the removal of a proton from the active site []. Beta-and gamma-CAs also employ a zinc hydroxide mechanism, although at least some beta-class enzymes do not have water directly coordinated to the metal ion. | Name | Carbonic anhydrase-related protein VIII |
Short Name | CARP_VIII | Type | Family |