Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Stimulation of Human Erythrocyte K-Cl Cotransport and Protein Phosphatase Type 2A by n-Ethylmaleimide: Role of Intracellular Mg++

Stimulation of Human Erythrocyte K-Cl Cotransport and Protein Phosphatase Type 2A by... An increase in the activity of membrane-associated protein phosphatase type 1 (mb-PP1) is associated with stimulation of erythrocyte K-Cl cotransport (KCC). We have recently proposed that membrane-associated protein phosphatase type 2A (mb-PP2A) is also involved in KCC regulation by cell swelling (Bize et al., 1999. Am. J. Physiol. 277:C899–C912). We used two protein phosphatase inhibitors, okadaic acid (OA) and calyculin A (CalA), and two KCC activating treatments, n-ethylmaleimide (NEM) and Mg i ++-depletion, and determined KCC transport activity and mb-PP1 and mb-PP2A activities. OA, an inhibitor of erythrocyte mb-PP2A, partially prevents stimulation of KCC activity by NEM but not by Mg i ++-depletion. CalA, an inhibitor of both mb-PP1 and mb-PP2A prevents stimulation of KCC activity by both treatments. NEM and Mg i ++-depletion inhibit mb-PP1 activity, suggesting that activation of KCC can take place in the absence of mb-PP1 activation. Mb-PP2A activity is stimulated in NEM-treated cells but not in Mg i ++-depleted cells. In NEM-treated cells, Mg i ++-depletion inhibits both KCC and mb-PP2A. In Mg i ++-depleted cells, NEM does not stimulate KCC or mb-PP2A. The strong correlation between KCC stimulation and mb-PP2A stimulation provides further support to the idea that mb-PP2A plays an important role in KCC regulation. Our results are consistent with the hypothesis that KCC regulation involves at least two distinguishable phosphorylation sites. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Stimulation of Human Erythrocyte K-Cl Cotransport and Protein Phosphatase Type 2A by n-Ethylmaleimide: Role of Intracellular Mg++

Loading next page...
 
/lp/springer_journal/stimulation-of-human-erythrocyte-k-cl-cotransport-and-protein-0ZO02eApOG

References (42)

Publisher
Springer Journals
Copyright
Copyright © Inc. by 2000 Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
DOI
10.1007/s002320001109
Publisher site
See Article on Publisher Site

Abstract

An increase in the activity of membrane-associated protein phosphatase type 1 (mb-PP1) is associated with stimulation of erythrocyte K-Cl cotransport (KCC). We have recently proposed that membrane-associated protein phosphatase type 2A (mb-PP2A) is also involved in KCC regulation by cell swelling (Bize et al., 1999. Am. J. Physiol. 277:C899–C912). We used two protein phosphatase inhibitors, okadaic acid (OA) and calyculin A (CalA), and two KCC activating treatments, n-ethylmaleimide (NEM) and Mg i ++-depletion, and determined KCC transport activity and mb-PP1 and mb-PP2A activities. OA, an inhibitor of erythrocyte mb-PP2A, partially prevents stimulation of KCC activity by NEM but not by Mg i ++-depletion. CalA, an inhibitor of both mb-PP1 and mb-PP2A prevents stimulation of KCC activity by both treatments. NEM and Mg i ++-depletion inhibit mb-PP1 activity, suggesting that activation of KCC can take place in the absence of mb-PP1 activation. Mb-PP2A activity is stimulated in NEM-treated cells but not in Mg i ++-depleted cells. In NEM-treated cells, Mg i ++-depletion inhibits both KCC and mb-PP2A. In Mg i ++-depleted cells, NEM does not stimulate KCC or mb-PP2A. The strong correlation between KCC stimulation and mb-PP2A stimulation provides further support to the idea that mb-PP2A plays an important role in KCC regulation. Our results are consistent with the hypothesis that KCC regulation involves at least two distinguishable phosphorylation sites.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Sep 15, 2000

There are no references for this article.