期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1997
卷号：94
期号：11
页码：5943-5948
DOI：10.1073/pnas.94.11.5943
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The objective of this study has been to determine which Na,K-ATPase isoforms are expressed in red blood cells and whether kinetic differences in the uncoupled sodium efflux mode between the human red blood cell Na,K-ATPase and other preparations can be explained by differences in the underlying subunit composition. To this end, human reticulocyte RNA was isolated, reverse transcribed, amplified by PCR and appropriate primers, and sequenced. Primers from highly conserved areas as well as isoform-specific primers were used. The 1 and 3 isoforms of the subunit, and the {beta}2 and {beta}3 isoforms of the {beta} subunit were found. The complete coding regions of the cDNAs for the reticulocyte subunits were sequenced from overlapping PCR fragments. No difference was found between the reticulocyte isoforms and the ones already known. The fact that we found {beta}2 but not {beta}1 in reticulocyte single-stranded cDNA, and {beta}1 but not {beta}2 in a leukocyte library indicates that leukocyte contamination of our reticulocyte preparation was negligible. Analysis of a human bone marrow library showed that 1, 2, and 3 as well as all three {beta} isoforms were present. The extent to which the kinetic properties of uncoupled sodium efflux might depend on different isoform combinations is not yet known.
