Subunit Interactions in the Sodium Pump<sup>a</sup>

Colonna, Thomas E.; Kostich, Mitch; Hamrick, M.; Hwang, B.; Rawn, J. David; Fambrough, Douglas M.

doi:10.1111/j.1749-6632.1997.tb52308.x

Cited by 11 publications

(2 citation statements)

References 26 publications

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“…Several excellent reviews describe the role of the β-subunit in stabilizing the α-subunit and facilitating its routing and insertion into the membrane, as well as effects on functional properties, notably cation affinities (86)(87)(88). The strongest subunit interactions exist between the extracellular loop L7/8 and the β-subunit (86-88), but membrane and cytoplasmic sequences also play a part (86,88).…”

Section: α- β- γ -Subunit Interactionsmentioning

confidence: 99%

Structure and Mechanism of Na,K-ATPase: Functional Sites and Their Interactions

Jørgensen

Håkansson

Karlish

2003

Annu. Rev. Physiol.

497

364

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The cell membrane Na,K-ATPase is a member of the P-type family of active cation transport proteins. Recently the molecular structure of the related sarcoplasmic reticulum Ca-ATPase in an E1 conformation has been determined at 2.6 A resolution. Furthermore, theoretical models of the Ca-ATPase in E2 conformations are available. As a result of these developments, these structural data have allowed construction of homology models that address the central questions of mechanism of active cation transport by all P-type cation pumps. This review relates recent evidence on functional sites of Na,K-ATPase for the substrate (ATP), the essential cofactor (Mg(2+) ions), and the transported cations (Na(+) and K(+)) to the molecular structure. The essential elements of the Ca-ATPase structure, including 10 transmembrane helices and well-defined N, P, and A cytoplasmic domains, are common to all PII-type pumps such as Na,K-ATPase and H,K-ATPases. However, for Na,K-ATPase and H,K-ATPase, which consist of both alpha- and beta-subunits, there may be some detailed differences in regions of subunit interactions. Mutagenesis, proteolytic cleavage, and transition metal-catalyzed oxidative cleavages are providing much evidence about residues involved in binding of Na(+), K(+), ATP, and Mg(2+) ions and changes accompanying E1-E2 or E1-P-E2-P conformational transitions. We discuss this evidence in relation to N, P, and A cytoplasmic domain interactions, and long-range interactions between the active site and the Na(+) and K(+) sites in the transmembrane segments, for the different steps of the catalytic cycle.

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Section: α- β- γ -Subunit Interactionsmentioning

confidence: 99%

Structure and Mechanism of Na,K-ATPase: Functional Sites and Their Interactions

Jørgensen

Håkansson

Karlish

2003

Annu. Rev. Physiol.

497

364

View full text Add to dashboard Cite

show abstract

“…Evidências experimentais sugerem que a subunidade β interage com a subunidade α em múltiplos sítios, os quais estão localizados tanto no ectodomínio quanto no segmento transmembrana e no domínio citoplasmático (Hasler et al, 1998(Hasler et al, , 2001. O sítio de interação entre estas subunidades, atualmente mais claramente definido, está localizado na alça extracitoplasmática entre os segmentos transmembrana M7 e M8 da subunidade α, que interage com o domínio β localizado dentro dos 64 aminoácidos adjacentes ao segmento transmembrana (Fambrough et al, 1994;Colonna et al, 1997;Jorgensen et al, 2003). A interação nesta região mostrou ser importante para a correta inserção na membrana da subunidade α da Na,K-ATPase (Beggah et al, 1997;Béguin et al, 1998Béguin et al, , 2000Hasler et al, 2001).…”

Section: Introdução 11 a Nak-atpaseunclassified