InterPro domain: IPR044690

The calcium sensing receptor (CAS) from Arabidopsis is a thylakoid-localised phosphoprotein that possesses a single transmembrane domain that splits the protein into two halves: the N-terminal domain which binds Ca2 with low affinity and high capacity, and the C-terminal domain that contains a non-catalytic rhodanese homology domain and phosphorylation sites [ 1 ]. It modulates cytoplasmic Ca2 levels and it is required for proper stomatal regulation in response to elevated levels of external Ca2 [ 2 ] and it is also involved in de-etiolation [ 3 ]. This protein also plays a role in the STN7/STN8/TAP38 network of phosphorylation-mediated photoacclimation processes in Arabidopsis [ 4 ].

1. The High Light Response in Arabidopsis Requires the Calcium Sensor Protein CAS, a Target of STN7- and STN8-Mediated Phosphorylation. Front Plant Sci 10, 974
2. Calcium-sensing receptor regulates stomatal closure through hydrogen peroxide and nitric oxide in response to extracellular calcium in Arabidopsis. J Exp Bot 63, 177-90
3. Calcium and calcium receptor CAS promote Arabidopsis thaliana de-etiolation. Physiol Plant 144, 73-82