In ileal Na+ absorptive cells, carbachol inhibits NaCl absorption and its component brush-border Na+/H+ exchanger, acting via basolateral membrane (BLM) receptors. This carbachol effect involves brush-border but not BLM protein kinase C. In the present work we describe another asymmetric aspect of signal transduction in these epithelial cells, this time involving phosphatidylinositol 4,5-bisphosphate (PIP2)-specific phospholipase C (PLC). Thirty seconds and 1 min after carbachol treatment, brush-border PIP2-specific PLC activity increased, returning to control levels by 2.5 min. Involvement of brush-border tyrosine kinase(s) in this effect was suggested by inhibition of the carbachol effect on NaCl absorption by the tyrosine kinase inhibitor genistein, added to the mucosal but not the serosal surface. Luminal genistein pretreatment also prevented the carbachol-induced increase in brush-border PLC activity. In contrast, carbachol exposure did not change the BLM PIP2-specific PLC activity. Western analysis and immunoprecipitation demonstrated that PLC-γ1 is present in the brush border and that carbachol increases the PLC-γ1 amount in the brush border. Both the brush border and BLM contain PLC-β3 and a small amount of PLC-∆1 but no PLC-β1, whereas BLM lacks detectable PLC-γ1. No change in PLC-β3 or PLC-∆1 amount in the brush border occurred with carbachol exposure. No change in tyrosine phosphorylation of brush-border PLC-γ1 occurred with carbachol treatment. The Ca2+ ionophore A23187 did not alter PIP2-specific PLC activity in either the brush border or the BLM. These studies demonstrate that carbachol but not Ca2+ ionophore effects on brush-border NaCl absorption are associated with increases in brush-border but not BLM PIP2-specific PLC activity and in the amount of brush-border PLC-γ1, and involve tyrosine phosphorylation. This asymmetric aspect of epithelial signal transduction, together with the previous demonstration of localization of high-sensitivity IP3 stores to the apical membrane area in intestinal epithelial cells, shows that different aspects of signal transduction occur at the apical and basolateral membranes in epithelia and requires studies in both domains to define mechanisms of intracellular signalling.
Skip Nav Destination
Follow us on Twitter @Biochem_Journal
Article navigation
January 1996
-
Cover Image
Cover Image
- PDF Icon PDF LinkTable of Contents
Research Article|
January 15 1996
Asymmetric signal transduction in polarized ileal Na+-absorbing cells: carbachol activates brush-border but not basolateral-membrane PIP2-PLC and translocates PLC-γ1 only to the brush border Available to Purchase
Seema KHURANA;
Seema KHURANA
*Departments of Medicine and Physiology, G. I. Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A.
Search for other works by this author on:
Anna ARONZON;
Anna ARONZON
*Departments of Medicine and Physiology, G. I. Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A.
Search for other works by this author on:
W. Alexandra HOOGERWERF;
W. Alexandra HOOGERWERF
*Departments of Medicine and Physiology, G. I. Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A.
Search for other works by this author on:
Sue Goo RHEE;
Sue Goo RHEE
‡Laboratory of Biochemistry, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, MD 20892, U.S.A.
Search for other works by this author on:
Mark DONOWITZ;
Mark DONOWITZ
§
*Departments of Medicine and Physiology, G. I. Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A.
§To whom correspondence should be addressed.
Search for other works by this author on:
Michael E. COHEN
Michael E. COHEN
*Departments of Medicine and Physiology, G. I. Division, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A.
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
May 09 1995
Revision Received:
September 06 1995
Accepted:
September 08 1995
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1996
1996
Biochem J (1996) 313 (2): 509–518.
Article history
Received:
May 09 1995
Revision Received:
September 06 1995
Accepted:
September 08 1995
Citation
Seema KHURANA, Sawsan KREYDIYYEH, Anna ARONZON, W. Alexandra HOOGERWERF, Sue Goo RHEE, Mark DONOWITZ, Michael E. COHEN; Asymmetric signal transduction in polarized ileal Na+-absorbing cells: carbachol activates brush-border but not basolateral-membrane PIP2-PLC and translocates PLC-γ1 only to the brush border. Biochem J 15 January 1996; 313 (2): 509–518. doi: https://doi.org/10.1042/bj3130509
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |