|
|
||||||||
-dependent mechanism
1 Renal Division, Department of Medicine, and 2 Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322
The Na-K-2Cl
cotransporter NKCC1 is an important volume-regulatory transporter that
is regulated by cell volume and intracellular Cl
. This
regulation appears to be mediated by phosphorylation of NKCC1, although
there is evidence for additional, cytoskeletal regulation via myosin
light chain (MLC) kinase. NKCC1 is also activated by growth factors and
may contribute to cell hypertrophy, but the mechanism is unknown. In
aortic endothelial cells, NKCC1 (measured as bumetanide-sensitive
86Rb+ influx) was rapidly stimulated by serum,
lysophosphatidic acid, and fibroblast growth factor, with the greatest
stimulation by serum. Serum increased bumetanide-sensitive influx
significantly more than bumetanide-sensitive efflux (131% vs. 44%),
indicating asymmetric stimulation of NKCC1, and produced a 17%
increase in cell volume and a 25% increase in Cl
content
over 15 min. Stimulation by serum and hypertonic shrinkage were
additive, and serum did not increase phosphorylation of NKCC1 or MLC,
and did not decrease cellular Cl
content. When cellular
Cl
was replaced with methanesulfonate, influx via NKCC1
increased and was no longer stimulated by serum, whereas stimulation by hypertonic shrinkage still occurred. Based on these results, we propose
a novel mechanism whereby serum activates NKCC1 by reducing its
sensitivity to inhibition by intracellular Cl
. This
resetting of the Cl
set point of the transporter enables
the cotransporter to produce a hypertrophic volume increase.
Na-K-2Cl cotransport; serum; lysophosphatidic acid; fibroblast growth factor; intracellular chloride; vascular endothelium
This article has been cited by other articles:
![]() |
H. I. Rocha-Gonzalez, S. Mao, and F. J. Alvarez-Leefmans Na+,K+,2Cl- Cotransport and Intracellular Chloride Regulation in Rat Primary Sensory Neurons: Thermodynamic and Kinetic Aspects J Neurophysiol, July 1, 2008; 100(1): 169 - 184. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Pieraut, V. Laurent-Matha, C. Sar, T. Hubert, I. Mechaly, C. Hilaire, M. Mersel, E. Delpire, J. Valmier, and F. Scamps NKCC1 Phosphorylation Stimulates Neurite Growth of Injured Adult Sensory Neurons J. Neurosci., June 20, 2007; 27(25): 6751 - 6759. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Jiang, F. Akar, S. L. Cobbs, K. Lomashvilli, R. Lakkis, F. J. Gordon, R. L. Sutliff, and W. C. O'Neill Blood pressure regulates the activity and function of the Na-K-2Cl cotransporter in vascular smooth muscle Am J Physiol Heart Circ Physiol, April 1, 2004; 286(4): H1552 - H1557. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Lytle and T. McManus Coordinate modulation of Na-K-2Cl cotransport and K-Cl cotransport by cell volume and chloride Am J Physiol Cell Physiol, November 1, 2002; 283(5): C1422 - C1431. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |