title: Regulation of connexin43 gap junctional communication by phosphatidylinositol 4,5-bisphosphate.
abstract: Cell-cell communication through connexin43 (Cx43)-based gap junction channels is rapidly inhibited upon activation of various G protein-coupled receptors; however, the mechanism is unknown. We show that Cx43-based cell-cell communication is inhibited by depletion of phosphatidylinositol 4,5-bisphosphate (PtdIns[4,5]P(2)) from the plasma membrane. Knockdown of phospholipase Cbeta3 (PLCbeta3) inhibits PtdIns(4,5)P(2) hydrolysis and keeps Cx43 channels open after receptor activation. Using a translocatable 5-phosphatase, we show that PtdIns(4,5)P(2) depletion is sufficient to close Cx43 channels. When PtdIns(4,5)P(2) is overproduced by PtdIns(4)P 5-kinase, Cx43 channel closure is impaired. We find that the Cx43 binding partner zona occludens 1 (ZO-1) interacts with PLCbeta3 via its third PDZ domain. ZO-1 is essential for PtdIns(4,5)P(2)-hydrolyzing receptors to inhibit cell-cell communication, but not for receptor-PLC coupling. Our results show that PtdIns(4,5)P(2) is a key regulator of Cx43 channel function, with no role for other second messengers, and suggest that ZO-1 assembles PLCbeta3 and Cx43 into a signaling complex to allow regulation of cell-cell communication by localized changes in PtdIns(4,5)P(2).
authors.affiliation: Division of Cellular Biochemistry, Centre for Biomedical Genetics, The Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands.
authors.forename: Leonie
authors.initials: L
authors.lastname: van Zeijl
authors.forename: Bas
authors.initials: B
authors.lastname: Ponsioen
authors.forename: Ben N G
authors.initials: BN
authors.lastname: Giepmans
authors.forename: Aafke
authors.initials: A
authors.lastname: Ariaens
authors.forename: Friso R
authors.initials: FR
authors.lastname: Postma
authors.forename: Péter
authors.initials: P
authors.lastname: Várnai
authors.forename: Tamas
authors.initials: T
authors.lastname: Balla
authors.forename: Nullin
authors.initials: N
authors.lastname: Divecha
authors.forename: Kees
authors.initials: K
authors.lastname: Jalink
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Moolenaar
mesh_terms: D000818:Animals; D002450:Cell Communication; D018031:Connexin 43 / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008959:Models, Neurological; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D054799:Phospholipase C beta; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
chemical_list: D018031:Connexin 43; D007527:Isoenzymes; D008565:Membrane Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D010750:Phosphoproteins; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D010738:Type C Phospholipases; D054799:Phospholipase C beta