IQUIFIB   02644
INSTITUTO DE QUIMICA Y FISICOQUIMICA BIOLOGICAS "PROF. ALEJANDRO C. PALADINI"
Unidad Ejecutora - UE
artículos
Título:
“Deletions in the A(L) region of the h4xb plasma membrane Ca(2+) pump. High apparent affinity for Ca(2+) of a deletion mutant resembling the alternative spliced form h4zb”
Autor/es:
DE TEZANOS PINTO FELICITAS; ADAMO HUGO PEDRO
Revista:
FEBS LETTERS
Referencias:
Año: 2006 vol. 580 p. 1576 - 1580
ISSN:
0014-5793
Resumen:
Mutants of the plasma membrane Ca2+ pump (human isoform 4xb) with deletions in the linker between domain A and transmembrane segment M3 (AL region) were constructed and expressed in Chinese hamster ovary cells. The total or partial removal of the amino acid segment 300-349 did not change the maximal Ca2+ transport activity, but mutants with deletions involving residues 300-338 exhibited a higher apparent affinity for Ca2+ than the wild type h4xb enzyme. Deletion of the putative acidic lipid interacting sequence (residues 339-349) had no observable functional consequences.  The removal of either residues 300-314 or 313-338 resulted in a similar increase in the apparent Ca2+ affinity of the pump although the increase was somewhat lower than that obtained by the deletion 300-349 suggesting that both deletions affected the same structural determinant.  The results show that alterations in the region of the alternative splicing site A change the sensitivity to Ca2+ of the human isoform 4 of the PMCA.