Cx43 phosphorylation on S279-282 and intercellular communication are regulated by IP3-IP3 receptor signalingReportar como inadecuado

Cx43 phosphorylation on S279-282 and intercellular communication are regulated by IP3-IP3 receptor signaling - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Cell Communication and Signaling

, 12:58

First Online: 28 September 2014Received: 02 December 2013Accepted: 11 September 2014


BackgroundInositol 1,4,5-trisphosphate receptor IP3R plays a pivotal role in the Ca release process in a variety of cell types. Additionally, IP3R is distributed in ventricular intercalated discs, but its functions in this particular site remains unknown. Connexin Cx43, the predominant gap junction GJ protein in ventricular myocardium, is linked to several signaling pathways that regulate Cx43 properties by dephosphorylation on multiple residues. Here, we investigated the regulatory role of IP3R in cell-cell communication and the mechanisms underlying this effect.

ResultsIn neonatal rat and adult mouse ventricular myocytes IP3R co-localized and co-immunoprecipitated with Cx43 in GJ plaques detected by immunostaining and western blot assays. Blocking IP3R with antagonists or silencing pan-IP3R expression with shRNA hindered the 6-carboxyfluorescein 6-CFDA diffusion through GJs and desynchronized Ca transients among confluent neonatal myocytes in culture, whereas stimulation of IP3R with IP3 ester or ATP exerted the opposite effect. Likewise, 6-CFDA propagation through GJs was modulated by IP3R activation or inhibition in cell pairs of isolated adult cardiomyocytes. Furthermore, IP3R activation or IP3R suppression promoted or suppressed, respectively, Cx43 phosphorylation on S279-282. Site-directed mutagenesis indicated that expression of a mutant Cx43-S282A alanine inhibited S279-282 phosphorylation and GJ permeability, while the S279A mutant showed the opposite effect in ventricular myocytes. Expression of these mutants in HEK293 cells revealed that cells with a dual S279-282 mutation failed to express exogenous Cx43, whereas cells with a single S279 or S282 mutation displayed Cx43 overexpression with increased phosphorylation of S279-282 and promotion of intercellular communication.

ConclusionsThese results demonstrated, for the first time, that IP3R physically interacts with Cx43 and participates in the regulation of Cx43 phosphorylation on S279-282, thereby affecting GJ intercellular communication in ventricular myocytes.

KeywordsInositol 1,4,5-trisphosphate receptor Gap junction Connexin 43 Serine 279-282 phosphorylation Intercellular communication Ventricular myocyte AbbreviationsIP3RInositol 1,4,5-trisphosphate receptor

LYLucifer yellow

Cx43Connexin 43

NRVMsNeonatal rat ventricular myocytes

FRAPFluorescence recovery after photobleach

HBSSHEPES-buffered salt solution

XeCXestospongin C

2-APB2-aminoethoxydiphenyl borate

6-CFDA6-carboxyfluorescein diacetate

EREndoplasmic reticulum

SRSarcoplasmic reticulum

S279-282Serines 279-282

S279A-282ASerine 279 and serine 282 with alanine

S282DSerine 282 with aspartic acid

GPCRG-protein coupled receptor

GAPDHGlyceraldehyde-3-phosphate dehydrogenase

Electronic supplementary materialThe online version of this article doi:10.1186-s12964-014-0058-6 contains supplementary material, which is available to authorized users.

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Autor: Man Kang - Na Lin - Chen Li - Qingli Meng - Yuanyuan Zheng - Xinxin Yan - Jianxin Deng - Yang Ou - Chao Zhang - Junqi He


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