| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
2 Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
* To whom correspondence should be addressed. E-mail: Chou-Long.Huang{at}UTSouthwestern.edu.
ROMK potassium channels are present in the cortical collecting ducts of kidney and serve as the exit pathways for K+ secretion in this nephron segment. Dietary K+ restriction reduces the abundance of ROMK in kidney. We have previously shown that ROMK undergoes endocytosis via clathrin coated vesicles (CCVs) in Xenopus oocytes and in cultured cells. Here, we examined the effect of dietary K+ restriction on endocytosis of ROMK in cortical collecting ducts (CCDs) using double labeling immunofluorescent staining and confocal microscopic imaging in whole kidney sections as well as in individually isolated tubules. We found that ROMK abundance in kidney cortex and CCDs was reduced in rats fed a K+-restricted diet as compared to rats fed the control K+ diet. In the control animals, ROMK staining was preferentially localized to the apical membrane of CCDs. Compared to the control tubules, ROMK staining in CCDs was markedly shifted toward to intracellular locations in animals fed K+-deficient diets for 48 hrs. Some of the intracellular distribution of ROMK co-localized with an early endosome marker, early endosomal antigen-1 (EEA-1) or with a late endosome/lysosome marker, lysosomal membrane glycoprotein-120 (LGP-120). These results suggest that K+-restriction reduces the abundance of ROMK in CCDs by increasing endocytosis and degradation of the channel protein. This decrease in the abundance of ROMK is likely important for maintaining K+ homeostasis during K+ deficiency.
This article has been cited by other articles:
|
|
 |
|
  D.-H. Lin, P. Yue, C.-Y. Pan, P. Sun, X. Zhang, Z. Han, M. Roos, M. Caplan, G. Giebisch, and W.-H. Wang POSH Stimulates the Ubiquitination and the Clathrin-independent Endocytosis of ROMK1 Channels J. Biol. Chem., October 23, 2009; 284(43): 29614 - 29624. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. A. Welling and K. Ho A comprehensive guide to the ROMK potassium channel: form and function in health and disease Am J Physiol Renal Physiol, October 1, 2009; 297(4): F849 - F863. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. A. Spector, Q. Yang, L. Klopouh, J. Deng, E. J. Weinman, D. A. Steplock, R. Biswas, M. F. Brazie, J. Liu, and J. B. Wade The ROMK potassium channel is present in mammalian urinary tract epithelia and muscle Am J Physiol Renal Physiol, December 1, 2008; 295(6): F1658 - F1665. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. D. Tobin, M. Tomaszewski, P. S. Braund, C. Hajat, S. M. Raleigh, T. M. Palmer, M. Caulfield, P. R. Burton, and N. J. Samani Common Variants in Genes Underlying Monogenic Hypertension and Hypotension and Blood Pressure in the General Population Hypertension, June 1, 2008; 51(6): 1658 - 1664. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Babilonia, D. Lin, Y. Zhang, Y. Wei, P. Yue, and W.-H. Wang Role of gp91phox-Containing NADPH Oxidase in Mediating the Effect of K Restriction on ROMK Channels and Renal K Excretion J. Am. Soc. Nephrol., July 1, 2007; 18(7): 2037 - 2045. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Babilonia, D. Li, Z. Wang, P. Sun, D.-H. Lin, Y. Jin, and W.-H. Wang Mitogen-Activated Protein Kinases Inhibit the ROMK (Kir 1.1)-Like Small Conductance K Channels in the Cortical Collecting Duct J. Am. Soc. Nephrol., October 1, 2006; 17(10): 2687 - 2696. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Pluznick and S. C. Sansom BK channels in the kidney: role in K+ secretion and localization of molecular components Am J Physiol Renal Physiol, September 1, 2006; 291(3): F517 - F529. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Najjar, H. Zhou, T. Morimoto, J. B. Bruns, H.-S. Li, W. Liu, T. R. Kleyman, and L. M. Satlin Dietary K+ regulates apical membrane expression of maxi-K channels in rabbit cortical collecting duct Am J Physiol Renal Physiol, October 1, 2005; 289(4): F922 - F932. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. C. Hebert, G. Desir, G. Giebisch, and W. Wang Molecular Diversity and Regulation of Renal Potassium Channels Physiol Rev, January 1, 2005; 85(1): 319 - 371. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Meneton, J. Loffing, and D. G. Warnock Sodium and potassium handling by the aldosterone-sensitive distal nephron: the pivotal role of the distal and connecting tubule Am J Physiol Renal Physiol, October 1, 2004; 287(4): F593 - F601. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
