AJP - Renal Physiology, Vol 273, Issue 5 718-F730, Copyright © 1997 by American Physiological Society

ARTICLES

Expression of syntaxins in rat kidney

B. Mandon, S. Nielsen, B. K. Kishore and M. A. Knepper
Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-0951, USA.

Previously, we demonstrated that a putative vesicle-targeting protein, syntaxin-4, is expressed in renal collecting duct principal cells and is localized to the apical plasma membrane, suggesting a role in targeting aquaporin-2-containing vesicles to the apical plasma membrane. To investigate whether other syntaxin isoforms are present in the renal collecting duct, we determined the intrarenal localization of syntaxin-2 and -3. Reverse transcription-polymerase chain reaction (RT-PCR) experiments using total RNA extracted from kidney and various organs revealed that both syntaxin-2 and -3 are expressed in kidney cortex and medulla. RT-PCR experiments using microdissected tubules and vascular structures from the kidney revealed that syntaxin-3 mRNA, but not syntaxin-2, is expressed in collecting duct cells. Syntaxin-3 mRNA was also relatively abundant in the thick ascending limb of Henle's loop and in vasa recta. Syntaxin-2 mRNA was found chiefly in glomeruli. To investigate the localization of syntaxin-3 protein, a peptide-derived polyclonal antibody was raised in rabbits. In immunoblotting experiments, this antibody labeled a 37-kDa protein in inner medulla that was most abundant in plasma membrane-enriched subcellular fractions. Immunoperoxidase labeling of thin cryosections combined with immunogold electron microscopy showed that, in contrast to the labeling seen for syntaxin-4, syntaxin-3 labeling in medullary collecting duct was predominantly in the basolateral plasma membrane of intercalated cells. These results suggest the possibility that syntaxin-3 may be involved in selective targeting of acid-base transporters and/or in basolateral membrane remodeling in response to systemic acid-base perturbations.

This article has been cited by other articles:

				T. Pisitkun, J. Bieniek, D. Tchapyjnikov, G. Wang, W. W. Wu, R.-F. Shen, and M. A. Knepper High-throughput identification of IMCD proteins using LC-MS/MS Physiol Genomics, April 13, 2006; 25(2): 263 - 276. [Abstract] [Full Text] [PDF]

				P. A. Ortiz cAMP increases surface expression of NKCC2 in rat thick ascending limbs: role of VAMP Am J Physiol Renal Physiol, March 1, 2006; 290(3): F608 - F616. [Abstract] [Full Text] [PDF]

				T.-J. Sun, W.-Z. Zeng, and C.-L. Huang Inhibition of ROMK potassium channel by syntaxin 1A Am J Physiol Renal Physiol, February 1, 2005; 288(2): F284 - F289. [Abstract] [Full Text] [PDF]

				C. A. Wagner, K. E. Finberg, S. Breton, V. Marshansky, D. Brown, and J. P. Geibel Renal Vacuolar H+-ATPase Physiol Rev, October 1, 2004; 84(4): 1263 - 1314. [Abstract] [Full Text] [PDF]

				D. Brown The ins and outs of aquaporin-2 trafficking Am J Physiol Renal Physiol, May 1, 2003; 284(5): F893 - F901. [Abstract] [Full Text] [PDF]

				H. L. Brooks, S. Ageloff, T.-H. Kwon, W. Brandt, J. M. Terris, A. Seth, L. Michea, S. Nielsen, R. Fenton, and M. A. Knepper cDNA array identification of genes regulated in rat renal medulla in response to vasopressin infusion Am J Physiol Renal Physiol, January 1, 2003; 284(1): F218 - F228. [Abstract] [Full Text] [PDF]

				X. Li, S. H. Low, M. Miura, and T. Weimbs SNARE expression and localization in renal epithelial cells suggest mechanism for variability of trafficking phenotypes Am J Physiol Renal Physiol, November 1, 2002; 283(5): F1111 - F1122. [Abstract] [Full Text] [PDF]

				W.-Z. Zeng, V. Babich, B. Ortega, R. Quigley, S. J. White, P. A. Welling, and C.-L. Huang Evidence for endocytosis of ROMK potassium channel via clathrin-coated vesicles Am J Physiol Renal Physiol, October 1, 2002; 283(4): F630 - F639. [Abstract] [Full Text] [PDF]