Calcium Binding Protein P22 (CHP)

SLC9A1BP; Calcineurin homologous protein; Calcineurin B-like protein; EF-hand calcium-binding domain-containing protein p22

SPN	U470
MGI	1927185
PubMed	10512881
RGD	620447
UniProt	Q99653
Wiki	CHP

Calcium binding protein P22 is a phosphoprotein that binds to the sodium-potassium exchangers (NHEs). This protein serves as an essential cofactor which supports the physiological activity of NHE family members. It has protein sequence similarity to calcineurin B and it is also known to be an endogenous inhibitor of calcineurin activity.

A partial sequence obtained from this screen was used to clone a novel full-length cDNA, designated CHP, from a second B-cell library. The deduced 195-amino acid protein contains 2 distinct and 2 potential EF-hand Ca(2+)-binding motifs and shares 43% and 33% identity with calcineurin B and calmodulin, respectively. It also shares 99% sequence identity with the rat homolog. Northern blot analysis demonstrated expression of a 4-kb CHP transcript in all 8 fetal tissues examined.

Reference

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"Calcineurin homologous protein as an essential cofactor for Na+/H+ exchangers."
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Biochemistry 43:3628-3636(2004) [PubMed] [Europe PMC] [Abstract]

"Nuclear-localized calcineurin homologous protein CHP1 interacts with upstream binding factor and inhibits ribosomal RNA synthesis."
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"Solution structure of the cytoplasmic region of Na+/H+ exchanger 1 complexed with essential cofactor calcineurin B homologous protein 1."
J. Biol. Chem. 282:2741-2751(2007) [PubMed] [Europe PMC] [Abstract]