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Transporter Information:
Name: ATPase, Na+/K+ transporting, beta 3 polypeptide
Symbol: ATP1B3
TC: 3.A.3.1.2
Locations: 3q22-q23
Swiss-Prot: P54709
Accession Number: NM_001679
PubMed (8798450): Malik N, Canfield VA, Beckers MC, Gros P, Levenson R. Identification of the mammalian Na,K-ATPase 3 subunit.J Biol Chem. 1996 Sep 13;271(37):22754-8. PMID: 8798450 [PubMed - indexed for MEDLINE]

We have isolated and characterized cDNA clones encoding the human and rat Na,K-ATPase beta3 subunit isoform. The human cDNA encodes a polypeptide of 279 amino acids that exhibits primary sequence and secondary structure similarities to Na,K-ATPase beta subunit isoforms. Sequence comparisons showed that the human beta3 subunit closely resembles the beta3 subunit of Xenopus laevis (59% amino acid identity) and is less similar to the human Na,K-ATPase beta1 and beta2 subunits (38% and 48% amino acid identity, respectively). By analyzing the segregation of restriction fragment length polymorphisms among recombinant inbred strains of mice, we localized the beta3 subunit gene to murine chromosome 7. Northern blot analysis revealed that the beta3 subunit gene encodes two transcripts that are expressed in a variety of rat tissues including testis, brain, kidney, lung, stomach, small intestine, colon, spleen, and liver. Identification of the mammalian beta3 subunit suggests an even greater potential for Na,K-ATPase isoenzyme diversity than previously realized.

PubMed (9457675): Malik N, Canfield V, Sanchez-Watts G, Watts AG, Scherer S, Beatty BG, GrosP, Levenson R. Structural organization and chromosomal localization of the human Na,K-ATPasebeta 3 subunit gene and pseudogene.Mamm Genome. 1998 Feb;9(2):136-43. PMID: 9457675 [PubMed - indexed for MEDLINE]

We have cloned and characterized the Na,K-ATPase beta 3 subunit gene (ATP1B3), and a beta 3 subunit pseudogene (ATP1B3P1), from a human PAC genomic library. The beta 3 subunit gene is > 50 kb in size and is split into 7 exons. The exon/intron organization of the beta 3 subunit gene is identical to that of the Na,K-ATPase beta 3 subunit gene, indicating that these two genes evolved from a common evolutionary ancestor. Comparison of the promoter region of the human and mouse beta 3 subunit gene reveals a high degree of homology within a 300-bp segment located immediately upstream of the translation start site, suggesting that control elements that serve to regulate the cell-specific expression of the beta 3 subunit gene are likely to be located within this conserved region. Dot blot analysis of beta 3 subunit transcripts revealed expression within virtually all human tissues, while in situ hybridization showed expression of beta 3 mRNA in both neurons and glia of rat brain. Fluorescence in situ hybridization with PAC DNA clones localized ATP1B3 to the q22-->23 region of Chromosome (Chr) 3, and the beta 3 pseudogene to the p13-->15 region of Chr 2.

>sp|P54709|AT1B3_HUMAN Sodium/potassium-transporting ATPase subunit beta-3 OS=Homo sapiens GN=ATP1B3 PE=1 SV=1