HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/1/C31    most recent 00447.2002v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Bize, I. Articles by Brugnara, C. Search for Related Content PubMed PubMed Citation Articles by Bize, I. Articles by Brugnara, C.

MEMBRANE TRANSPORTERS, ION CHANNELS, AND PUMPS

Regulation of K-Cl cotransport during reticulocyte maturation and erythrocyte aging in normal and sickle erythrocytes

Departments of Cell Biology, Harvard Medical School, and Department of Laboratory Medicine, Children's Hospital Boston, Boston, Massachusetts 02115

Submitted 27 September 2002 ; accepted in final form 22 February 2003

The age/density-dependent decrease in K-Cl cotransport (KCC), PP1 and PP2A activities in normal and sickle human erythrocytes, and the effect of urea, a known KCC activator, were studied using discontinuous, isotonic gradients. In normal erythrocytes, the densest fraction (d 33.4 g/dl) has only about 5% of the KCC and 4% of the membrane (mb)-PP1 activities of the least-dense fraction (d 24.7 g/dl). In sickle and normal erythrocytes, density-dependent decreases for mb-PP1 activity were similar (d_50% 28.1 ± 0.4 vs. 27.2 ± 0.2 g/dl, respectively), whereas those for KCC activity were not (d_50% 31.4 ± 0.9 vs. 26.8 ± 0.3 g/dl, respectively, P = 0.004). Excluding the 10% least-dense cells, a very tight correlation exists between KCC and mb-PP1 activities in normal (r² = 0.995) and sickle erythrocytes (r² = 0.93), but at comparable mb-PP1 activities, KCC activity is higher in sickle erythrocytes, suggesting a defective, mb-PP1-independent KCC regulation. In normal, least-dense but not in densest cells, urea stimulates KCC (two- to fourfold) and moderately increases mb-PP1 (20–40%). Thus mb-PP1 appears to mediate part of urea-stimulated KCC activity.

phosphorylation; protein phosphatase; urea; cell size; density

This article has been cited by other articles:

				C. H. Joiner, R. Kirk Rettig, M. Jiang, M. Risinger, and R. S. Franco Urea stimulation of KCl cotransport induces abnormal volume reduction in sickle reticulocytes Blood, February 15, 2007; 109(4): 1728 - 1735. [Abstract] [Full Text] [PDF]

				V. L. Lew and R. M. Bookchin Ion Transport Pathology in the Mechanism of Sickle Cell Dehydration Physiol Rev, January 1, 2005; 85(1): 179 - 200. [Abstract] [Full Text] [PDF]

				C. H. Joiner, R. K. Rettig, M. Jiang, and R. S. Franco KCl cotransport mediates abnormal sulfhydryl-dependent volume regulation in sickle reticulocytes Blood, November 1, 2004; 104(9): 2954 - 2960. [Abstract] [Full Text] [PDF]