| Primary Identifier | IPR002987 | Type | Family |
| Short Name | NaCa_exhngr1 |
| description | Na+/Ca2+exchange proteins are involved in maintaining Ca2+homeostasis ina wide variety of cell types. They are found in both the plasma membraneand intracellular organellar membranes, where they exchange Na+for Ca2+inan electrogenic manner. When located in the plasma membrane, they generallyutilise the transmembrane (TM) Na+concentration gradient in order toextrude Ca2+from cells. Three mammalian isoforms have been cloned to date(NCX1-3), which consist of 920-970 amino acid residues that are predictedto possess 11 or 12 TM domains. Interestingly, they possess a short motif(~30 residues) that is similar to the Na+/K+-ATPase, although its functionis unknown [, ].NCX1 is the principal Na+/Ca2+exchanger of cardiac myocytes, where it isthought to play an important role in excitation-contraction coupling. It isalso found in a variety of other tissues, suggesting it serves as ahousekeeping protein, maintaining low cytosolic Ca2+concentration. Alternativelyspliced variants of NCX1 have been identified, expression of which is celltype-specific. Sequence analysis reveals two sets of tandem repeats arefound within the NCX1 protein sequence, which are usually referred to asalpha and beta. The alpha repeats are thought to be involved in the ionbinding and translocation reactions of the exchanger, and the first betarepeat may be part of a regulatory site that responds to Ca2+concentration. |
