Calx_beta

Domains in Na-Ca exchangers and integrin-beta4

• SMART accession number: SM00237
• Description: Domain in Na-Ca exchangers and integrin subunit beta4 (and some cyanobacterial proteins)
• Interpro abstract (IPR003644):

  The calx-beta motif is present as a tandem repeat in the cytoplasmic domains of Calx Na-Ca exchangers, which are used to expel calcium from cells. This motif overlaps domains used for calcium binding and regulation. The calx-beta motif is also present in the cytoplasmic tail of mammalian integrin-beta4, which mediates the bi-directional transfer of signals across the plasma membrane, as well as in some cyanobacterial proteins. This motif contains a series of beta-strands and turns that form a self-contained beta-sheet [(PUBMED:9294196), (PUBMED:10390612)].

• GO process: cell communication (GO:0007154)
• GO component: integral to membrane (GO:0016021)

There are 2456 Calx_beta domains in 819 proteins in SMART's nrdb database.

Literature (relevant references for this domain)

Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.

• Schwarz EM, Benzer S
• Calx, a Na-Ca exchanger gene of Drosophila melanogaster.
• Proc Natl Acad Sci U S A. 1997; 94: 10249-54

We have cloned Calx, a gene that encodes a Na-Ca exchanger of Drosophila melanogaster. Calx encodes two repeated motifs, Calx-alpha and Calx-beta, that overlap domains required for exchanger activity and regulation. Calx has multiple transcripts in adults, including at least one expressed in the retina. The Calx genomic locus comprises >/=35 kb between the Atpalpha and rudimentary-like genes in chromosomal region 93B. In Xenopus oocytes, microinjected Calx cRNA induces calcium uptake like that of its homolog, the 3Na+-1Ca2+ exchanger of mammalian heart. Implications of Calx-alpha motifs for the mechanism of Na-Ca exchange are discussed.

Metabolism (metabolic pathways involving proteins which contain this domain)

% proteins involved	KEGG pathway ID	Description
47.50	map04020	Calcium signaling pathway
12.50	map04810	Regulation of actin cytoskeleton
12.50	map04512	ECM-receptor interaction
12.50	map04510	Focal adhesion
5.00	map00511	N-Glycan degradation
5.00	map00500	Starch and sucrose metabolism
5.00	map01032	Glycan structures - degradation

This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with Calx_beta domain which could be assigned to a KEGG orthologous group, and not all proteins containing Calx_beta domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.

Structure (3D structures containing this domain)

3D Structures of Calx_beta domains in PDB

PDB code	Title
2dpk	The crystal structure of the primary ca2+ sensor of the na+/ca2+ exchanger
2fws	First ca2+ binding domain of the na,ca-exchanger (ncx1)
2fwu	Second ca2+ binding domain of the na,ca-exchanger (ncx1)
2kls	Apo-form of the second ca2+ binding domain of ncx1.4
2klt	Second ca2+ binding domain of ncx1.3
2qvk	The second ca2+-binding domain of the na+-ca2+ exchanger is essential for regulation: crystal structures and mutational analysis
2qvm	The second ca2+-binding domain of the na+-ca2+ exchanger is essential for regulation: crystal structures and mutational analysis
3e9t	Crystal structure of apo-form calx cbd1 domain
3e9u	Crystal structure of calx cbd2 domain
3ead	Crystal structure of calx-cbd1
3fq4	Crystal structure of the calx-beta domain of integrin beta4
3fso	Crystal structure of the calx-beta domain of integrin beta4, calcium soak
3gin	Crystal structure of e454k-cbd1
3h6a	Structure of the calx-beta domain of integrin beta4 crystallized in the presence of calcium

Links (links to other resources describing this domain)

• INTERPRO: IPR003644