Interaction of c-Src with gap junction protein connexin-43. Role in the regulation of cell-cell communication.
Cell-cell communication via connexin-43 (Cx43)-based gap junctions is transiently inhibited by certain mitogens, but the underlying regulatory mechanisms are incompletely understood. Our previous studies have implicated the c-Src tyrosine kinase in mediating transient closure of Cx43-based gap junctions in normal fibroblasts. Here we show that activated c-Src (c-SrcK(+)) phosphorylates the COOH-terminal tail of Cx43, both in vitro and in intact cells. Coimmunoprecipitation experiments reveal that Cx43 associates with c-SrcK(+) and, to a lesser extent, with wild-type c-Src, but not with kinase-dead c-Src. Mutation of residue Cx43 Tyr(265) (Cx43-Y265F mutant) abolishes both tyrosine phosphorylation of Cx43 and its coprecipitation with c-Src. Expression of c-SrcK(+) in Rat-1 cells disrupts gap junctional communication. Strikingly, the communication-defective phenotype is bypassed after coexpression of the Cx43-Y265F mutant or a COOH-terminally truncated version of Cx43 (Cx43Delta263) that lacks residue Tyr(265). Our results support a model in which activated c-Src phosphorylates the COOH-terminal tail of Cx43 on residue Tyr(265), resulting in a stable interaction between both proteins leading to inhibition of gap junctional communication.
Giepmans
B N
BN
Division of Cellular Biochemistry, The Netherlands Cancer Institute and Centre for Biomedical Genetics, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Hengeveld
T
T
Postma
F R
FR
Moolenaar
W H
WH
D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002450:Cell Communication; D002460:Cell Line; D018031:Connexin 43 / Q000502:physiology*; D017629:Gap Junctions / Q000502:physiology; D006801:Humans; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D014162:Transfection; D019061:src-Family Kinases
D018031:Connexin 43; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human