A role for calcium-activated adenylate cyclase and protein kinase a in the lens src family kinase and Na,K-ATPase response to hyposmotic stress

Research output: Research - peer-reviewArticle

Abstract

PURPOSE. Na,K-ATPase activity in lens epithelium is subject to control by Src family tyrosine kinases (SFKs). Previously we showed hyposmotic solution causes an SFK-dependent increase in Na,K-ATPase activity in the epithelium. Here we explored the role of cAMP in the signaling mechanism responsible for the SFK and Na,K-ATPase response. METHODS. Intact porcine lenses were exposed to hyposmotic Krebs solution (200 mOsm) then the epithelium was assayed for cAMP, SFK phosphorylation (activation) or Na,K-ATPase activity. RESULTS. An increase of cAMP was observed in the epithelium of lenses exposed to hyposmotic solution. In lenses exposed to hyposmotic solution SFK phosphorylation in the epithelium approximately doubled as did Na,K-ATPase activity and both responses were prevented by H89, a protein kinase A inhibitor. The magnitude of the SFK response to hyposmotic solution was reduced by a TRPV4 antagonist HC067047 added to prevent TRPV4- mediated calcium entry, and by a cytoplasmic Ca2+ chelator BAPTA-AM. The Na,K-ATPase activity response in the epithelium of lenses exposed to hyposmotic solution was abolished by BAPTA-AM. As a direct test of cAMP-dependent SFK activation, intact lenses were exposed to 8-pCPT-cAMP, a cell-permeable cAMP analog. 8-pCPT-cAMP caused robust SFK activation. Using Western blot, two calcium-activated adenylyl cyclases, ADCY3 and ADCY8, were detected in lens epithelium. CONCLUSIONS. Calcium-activated adenylyl cyclases are expressed in the lens epithelium and SFK activation is linked to a rise of cAMP that occurs upon hyposmotic challenge. The findings point to cAMP as a link between TRPV4 channel-mediated calcium entry, SFK activation, and a subsequent increase of Na,K-ATPase activity.

LanguageEnglish (US)
Pages4447-4456
Number of pages10
JournalInvestigative Ophthalmology and Visual Science
Volume58
Issue number11
DOIs
StatePublished - Sep 1 2017

Fingerprint

Adenylate Kinase
src-Family Kinases
Adenylyl Cyclases
Protein Kinases
Lenses
Calcium
sodium-translocating ATPase
Epithelium
Phosphorylation
1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
Calcium Channels
Protein Kinase Inhibitors
Chelating Agents
Cyclic AMP-Dependent Protein Kinases
Swine
Western Blotting
Krebs-Ringer solution
N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide

Keywords

  • Calcium-activated adenylyl cyclase
  • cAMP
  • Lens
  • Na,K-ATPase
  • Src family kinase

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

@article{344fcec124874dccbaa933cae8f38d14,
title = "A role for calcium-activated adenylate cyclase and protein kinase a in the lens src family kinase and Na,K-ATPase response to hyposmotic stress",
abstract = "PURPOSE. Na,K-ATPase activity in lens epithelium is subject to control by Src family tyrosine kinases (SFKs). Previously we showed hyposmotic solution causes an SFK-dependent increase in Na,K-ATPase activity in the epithelium. Here we explored the role of cAMP in the signaling mechanism responsible for the SFK and Na,K-ATPase response. METHODS. Intact porcine lenses were exposed to hyposmotic Krebs solution (200 mOsm) then the epithelium was assayed for cAMP, SFK phosphorylation (activation) or Na,K-ATPase activity. RESULTS. An increase of cAMP was observed in the epithelium of lenses exposed to hyposmotic solution. In lenses exposed to hyposmotic solution SFK phosphorylation in the epithelium approximately doubled as did Na,K-ATPase activity and both responses were prevented by H89, a protein kinase A inhibitor. The magnitude of the SFK response to hyposmotic solution was reduced by a TRPV4 antagonist HC067047 added to prevent TRPV4- mediated calcium entry, and by a cytoplasmic Ca2+ chelator BAPTA-AM. The Na,K-ATPase activity response in the epithelium of lenses exposed to hyposmotic solution was abolished by BAPTA-AM. As a direct test of cAMP-dependent SFK activation, intact lenses were exposed to 8-pCPT-cAMP, a cell-permeable cAMP analog. 8-pCPT-cAMP caused robust SFK activation. Using Western blot, two calcium-activated adenylyl cyclases, ADCY3 and ADCY8, were detected in lens epithelium. CONCLUSIONS. Calcium-activated adenylyl cyclases are expressed in the lens epithelium and SFK activation is linked to a rise of cAMP that occurs upon hyposmotic challenge. The findings point to cAMP as a link between TRPV4 channel-mediated calcium entry, SFK activation, and a subsequent increase of Na,K-ATPase activity.",
keywords = "Calcium-activated adenylyl cyclase, cAMP, Lens, Na,K-ATPase, Src family kinase",
author = "Mohammad Shahidullah and Amritlal Mandal and Delamere, {Nicholas A.}",
year = "2017",
month = "9",
doi = "10.1167/iovs.17-21600",
volume = "58",
pages = "4447--4456",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "11",

}

TY - JOUR

T1 - A role for calcium-activated adenylate cyclase and protein kinase a in the lens src family kinase and Na,K-ATPase response to hyposmotic stress

AU - Shahidullah,Mohammad

AU - Mandal,Amritlal

AU - Delamere,Nicholas A.

PY - 2017/9/1

Y1 - 2017/9/1

N2 - PURPOSE. Na,K-ATPase activity in lens epithelium is subject to control by Src family tyrosine kinases (SFKs). Previously we showed hyposmotic solution causes an SFK-dependent increase in Na,K-ATPase activity in the epithelium. Here we explored the role of cAMP in the signaling mechanism responsible for the SFK and Na,K-ATPase response. METHODS. Intact porcine lenses were exposed to hyposmotic Krebs solution (200 mOsm) then the epithelium was assayed for cAMP, SFK phosphorylation (activation) or Na,K-ATPase activity. RESULTS. An increase of cAMP was observed in the epithelium of lenses exposed to hyposmotic solution. In lenses exposed to hyposmotic solution SFK phosphorylation in the epithelium approximately doubled as did Na,K-ATPase activity and both responses were prevented by H89, a protein kinase A inhibitor. The magnitude of the SFK response to hyposmotic solution was reduced by a TRPV4 antagonist HC067047 added to prevent TRPV4- mediated calcium entry, and by a cytoplasmic Ca2+ chelator BAPTA-AM. The Na,K-ATPase activity response in the epithelium of lenses exposed to hyposmotic solution was abolished by BAPTA-AM. As a direct test of cAMP-dependent SFK activation, intact lenses were exposed to 8-pCPT-cAMP, a cell-permeable cAMP analog. 8-pCPT-cAMP caused robust SFK activation. Using Western blot, two calcium-activated adenylyl cyclases, ADCY3 and ADCY8, were detected in lens epithelium. CONCLUSIONS. Calcium-activated adenylyl cyclases are expressed in the lens epithelium and SFK activation is linked to a rise of cAMP that occurs upon hyposmotic challenge. The findings point to cAMP as a link between TRPV4 channel-mediated calcium entry, SFK activation, and a subsequent increase of Na,K-ATPase activity.

AB - PURPOSE. Na,K-ATPase activity in lens epithelium is subject to control by Src family tyrosine kinases (SFKs). Previously we showed hyposmotic solution causes an SFK-dependent increase in Na,K-ATPase activity in the epithelium. Here we explored the role of cAMP in the signaling mechanism responsible for the SFK and Na,K-ATPase response. METHODS. Intact porcine lenses were exposed to hyposmotic Krebs solution (200 mOsm) then the epithelium was assayed for cAMP, SFK phosphorylation (activation) or Na,K-ATPase activity. RESULTS. An increase of cAMP was observed in the epithelium of lenses exposed to hyposmotic solution. In lenses exposed to hyposmotic solution SFK phosphorylation in the epithelium approximately doubled as did Na,K-ATPase activity and both responses were prevented by H89, a protein kinase A inhibitor. The magnitude of the SFK response to hyposmotic solution was reduced by a TRPV4 antagonist HC067047 added to prevent TRPV4- mediated calcium entry, and by a cytoplasmic Ca2+ chelator BAPTA-AM. The Na,K-ATPase activity response in the epithelium of lenses exposed to hyposmotic solution was abolished by BAPTA-AM. As a direct test of cAMP-dependent SFK activation, intact lenses were exposed to 8-pCPT-cAMP, a cell-permeable cAMP analog. 8-pCPT-cAMP caused robust SFK activation. Using Western blot, two calcium-activated adenylyl cyclases, ADCY3 and ADCY8, were detected in lens epithelium. CONCLUSIONS. Calcium-activated adenylyl cyclases are expressed in the lens epithelium and SFK activation is linked to a rise of cAMP that occurs upon hyposmotic challenge. The findings point to cAMP as a link between TRPV4 channel-mediated calcium entry, SFK activation, and a subsequent increase of Na,K-ATPase activity.

KW - Calcium-activated adenylyl cyclase

KW - cAMP

KW - Lens

KW - Na,K-ATPase

KW - Src family kinase

UR - http://www.scopus.com/inward/record.url?scp=85028935843&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85028935843&partnerID=8YFLogxK

U2 - 10.1167/iovs.17-21600

DO - 10.1167/iovs.17-21600

M3 - Article

VL - 58

SP - 4447

EP - 4456

JO - Investigative Ophthalmology and Visual Science

T2 - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 11

ER -