Limits...
v-Src phosphorylation of connexin 43 on Tyr247 and Tyr265 disrupts gap junctional communication.

Lin R, Warn-Cramer BJ, Kurata WE, Lau AF - J. Cell Biol. (2001)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Molecular Carcinogenesis Section, Cancer Research Center of Hawaii, Honolulu, HI 96813, USA.

ABSTRACT
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.

Show MeSH

Related in: MedlinePlus

A model for the interaction of v-Src with Cx43. In this model, the binding of Cx43 to v-Src is dependent upon SH3 and SH2 domain interactions, which are important for v-Src–induced phosphorylation of Cx43 at the Y265 site and the subsequent phosphorylation at the Y247 site, leading to closure of the Cx43 channel (details described in Discussion). PXXP denotes the proline-rich sequence of Cx43 P274–P284 that interacts with the SH3 domain of v-Src. For simplicity, gap junction channels are represented as cylinders. PM stands for plasma membrane.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2196463&req=5

fig8: A model for the interaction of v-Src with Cx43. In this model, the binding of Cx43 to v-Src is dependent upon SH3 and SH2 domain interactions, which are important for v-Src–induced phosphorylation of Cx43 at the Y265 site and the subsequent phosphorylation at the Y247 site, leading to closure of the Cx43 channel (details described in Discussion). PXXP denotes the proline-rich sequence of Cx43 P274–P284 that interacts with the SH3 domain of v-Src. For simplicity, gap junction channels are represented as cylinders. PM stands for plasma membrane.

Mentions: These observations suggest a working model for how v-Src interacts with and phosphorylates Cx43 on tyrosine and disrupts GJC (Fig. 8) . This model is a modification of the one proposed by Kanemitsu et al. (1997). The binding of Cx43 to v-Src is initiated by the interaction of the P274-P284 proline-rich region of Cx43 with the SH3 domain of v-Src. This interaction leads to phosphorylation of Cx43 at the Y265 site by the kinase domain of v-Src. Phosphorylation at Y265 provides a binding site for the SH2 domain of v-Src, which stabilizes the binding of Cx43 to v-Src. In our revised model, the kinase domain of v-Src can now efficiently phosphorylate Cx43 at the Y247 site, which may represent the key molecular event triggering the closure of the Cx43 channel by v-Src.


v-Src phosphorylation of connexin 43 on Tyr247 and Tyr265 disrupts gap junctional communication.

Lin R, Warn-Cramer BJ, Kurata WE, Lau AF - J. Cell Biol. (2001)

A model for the interaction of v-Src with Cx43. In this model, the binding of Cx43 to v-Src is dependent upon SH3 and SH2 domain interactions, which are important for v-Src–induced phosphorylation of Cx43 at the Y265 site and the subsequent phosphorylation at the Y247 site, leading to closure of the Cx43 channel (details described in Discussion). PXXP denotes the proline-rich sequence of Cx43 P274–P284 that interacts with the SH3 domain of v-Src. For simplicity, gap junction channels are represented as cylinders. PM stands for plasma membrane.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196463&req=5

fig8: A model for the interaction of v-Src with Cx43. In this model, the binding of Cx43 to v-Src is dependent upon SH3 and SH2 domain interactions, which are important for v-Src–induced phosphorylation of Cx43 at the Y265 site and the subsequent phosphorylation at the Y247 site, leading to closure of the Cx43 channel (details described in Discussion). PXXP denotes the proline-rich sequence of Cx43 P274–P284 that interacts with the SH3 domain of v-Src. For simplicity, gap junction channels are represented as cylinders. PM stands for plasma membrane.
Mentions: These observations suggest a working model for how v-Src interacts with and phosphorylates Cx43 on tyrosine and disrupts GJC (Fig. 8) . This model is a modification of the one proposed by Kanemitsu et al. (1997). The binding of Cx43 to v-Src is initiated by the interaction of the P274-P284 proline-rich region of Cx43 with the SH3 domain of v-Src. This interaction leads to phosphorylation of Cx43 at the Y265 site by the kinase domain of v-Src. Phosphorylation at Y265 provides a binding site for the SH2 domain of v-Src, which stabilizes the binding of Cx43 to v-Src. In our revised model, the kinase domain of v-Src can now efficiently phosphorylate Cx43 at the Y247 site, which may represent the key molecular event triggering the closure of the Cx43 channel by v-Src.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Molecular Carcinogenesis Section, Cancer Research Center of Hawaii, Honolulu, HI 96813, USA.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus