Lin R, Warn-Cramer BJ, Kurata WE, Lau AF.. v-Src phosphorylation of connexin 43 on Tyr247 and Tyr265 disrupts gap junctional communication. J Cell Biol 154: 815-827

Department of Cell and Molecular Biology , University of Hawaiʻi at Mānoa, Honolulu, Hawaii, United States
The Journal of Cell Biology (Impact Factor: 9.83). 09/2001; 154(4):815-27. DOI: 10.1083/jcb.200102027
Source: PubMed


The mechanism by which v-Src disrupts connexin (Cx)43 intercellular gap junctional communication (GJC) is not clear. In this study, we determined that Tyr247 (Y247) and the previously identified Tyr265 (Y265) site of Cx43 were the primary phosphorylation targets for activated Src in vitro. We established an in vivo experimental system by stably expressing v-Src and wild-type (wt) Cx43, or Y247F, Y265F, or Y247F/Y265F Cx43 mutants in a Cx43 knockout mouse cell line. Wt and mutant Cx43 localized to the plasma membrane in the absence or presence of v-Src. When coexpressed with v-Src, the Y247F, Y265F, and Y247F/Y265F Cx43 mutants exhibited significantly reduced levels of tyrosine phosphorylation compared with wt Cx43, indicating that Y247 and Y265 were phosphorylation targets of v-Src in vivo. Most importantly, GJC established by the Y247F, Y265F, and Y247F/Y265F Cx43 mutants was resistant to disruption by v-Src. Furthermore, we did not find evidence for a role for mitogen-activated protein kinase in mediating the disruption of GJC by v-Src. We conclude that phosphorylation on Y247 and Y265 of Cx43 is responsible for disrupting GJC in these mammalian cells expressing v-Src.

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    • " , a proline - rich region ( amino acids 274 – 284 ) and then phosphorylates tyrosine 265 providing an SH2 - binding domain with the subse - quent phosphorylation at tyrosine 247 ( Fig . 1C ) ( Kanemitsu et al . , 1997 ) . As a consequence of these phosphorylations gap junctional intercellular communica - tion is reduced ( Swenson et al . , 1990 ; Lin et al . , 2001 ; Giepmans et al . , 2001a ) and Cx43 turnover is initiated ( Solan and Lampe , 2014 ) . Interestingly , NMR studies show that although binding of Src is confined to the SH3 - binding domain of Cx43CT , conformational changes resulting from this binding extend for large distances along the Cx43CT ( Sorgen et al . , 2004 ) affecting the "
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    • "A study on Cx43 mutants has implied that phosphorylation of Tyr265 alone is not sufficient for complete gap junction closure. Instead, phosphorylation of both Tyr265 and Tyr247 are required to disrupt metabolic coupling through Cx43 gap junction channels (Lin et al., 2001). Together, these results support a model for v-Src induced Cx43 tyrosine phosphorylation, where interaction is initiated by binding of the v-Src SH3 domain to the Pro274-Pro284 region of Cx43. "
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    • "However, contrary results have been published by Swenson, et al. (1990) and Lin et al. (2001), who showed that Y265 and Y247 are required for v-src induced disruption of coupling in both Xenopus oocytes (Swenson et al. 1990) and in a mouse Cx43 knockout cell line transfected with different Cx43 mutants (Lin et al. 2001). In the latter study, the ERK1/2 phosphorylation sites (S255, 279, and 282) were found not to be required for closure. "
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