Key Connexin 43 Phosphorylation Events Regulate the Gap Junction Life Cycle
- 15 July 2007
- journal article
- research article
- Published by Springer Science and Business Media LLC in The Journal of Membrane Biology
- Vol. 217 (1-3), 35-41
- https://doi.org/10.1007/s00232-007-9035-y
Abstract
Connexin 43 (Cx43), the most widely expressed and abundant vertebrate gap junction protein, is phosphorylated at multiple different serine residues during its life cycle. Cx43 is phosphorylated soon after synthesis and phosphorylation changes as it traffics through the endoplasmic reticulum and Golgi to the plasma membrane, ultimately forming a gap junction structure. The electrophoretic mobility of Cx43 changes as the protein proceeds through its life cycle, with prominent bands often labeled P0, P1 and P2. Many reports have indicated changes in “phosphorylation” based on these mobility shifts and others that occur in response to growth factors or other biological effectors. Here, we indicate how phosphospecific and epitope-specific antibodies can be utilized to show when and where certain phosphorylation events occur during the Cx43 life cycle. These reagents show that phosphorylation at S364 and/or S365 is involved in forming the P1 isoform, an event that apparently regulates trafficking to or within the plasma membrane. Phosphorylation at S325, S328 and/or S330 is necessary to form a P2 isoform; and this phosphorylation event is present only in gap junctions. Treatment with protein kinase C activators led to phosphorylation at S368, S279/S282 and S262 with a shift in mobility in CHO, but not MDCK, cells. The shift was dependent on mitogen-activated protein kinase activity but not phosphorylation at S279/S282. However, phosphorylation at S262 could explain the shift. By defining these phosphorylation events, we have begun to sort out the critical signaling pathways that regulate gap junction function.This publication has 21 references indexed in Scilit:
- The C-terminus of connexin43 adopts different conformations in the Golgi and gap junction as detected with structure-specific antibodiesBiochemical Journal, 2007
- Analysis of Connexin43 phosphorylated at S325, S328 and S330 in normoxic and ischemic heartJournal of Cell Science, 2006
- Phosphorylation of serine 262 in the gap junction protein connexin-43 regulates DNA synthesis in cell-cell contact forming cardiomyocytesJournal of Cell Science, 2004
- Connexin43 phosphorylation at S368 is acute during S and G2/M and in response to protein kinase C activationJournal of Cell Science, 2003
- Ischemic preconditioning preserves connexin 43 phosphorylation during sustained ischemia in pig hearts in vivoThe FASEB Journal, 2003
- Beyond the gap: functions of unpaired connexon channelsNature Reviews Molecular Cell Biology, 2003
- Casein Kinase 1 Regulates Connexin-43 Gap Junction AssemblyPublished by Elsevier BV ,2002
- Palmitoylation of Endothelin Receptor APublished by Elsevier BV ,1996
- Differential phosphorylation of the gap junction protein connexin43 in junctional communication-competent and -deficient cell lines.The Journal of cell biology, 1990
- Regulation of Intercellular Communication and Growth by the Cellular src Gene aAnnals of the New York Academy of Sciences, 1988