Connexin 43 K63-polyubiquitination on lysines 264 and 303 regulates gap junction internalization
| Autor: | Charles G. Fisher, Rachael M. Kells-Andrews, Rachel A. Margraf, Matthias M. Falk |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
MAPK/ERK pathway media_common.quotation_subject Lysine Mutant Connexin macromolecular substances Biology Arginine Endocytosis Antibodies Madin Darby Canine Kidney Cells 03 medical and health sciences 0302 clinical medicine Dogs Ubiquitin Animals Humans Phosphorylation Internalization Protein kinase C 030304 developmental biology media_common 0303 health sciences Chemistry Cell Membrane Ubiquitination Gap junction Gap Junctions Cell Biology Cell biology Molecular Weight 030104 developmental biology Connexin 43 biology.protein sense organs 030217 neurology & neurosurgery HeLa Cells Research Article |
| Zdroj: | Journal of Cell Science. |
| ISSN: | 1477-9137 0021-9533 |
| DOI: | 10.1242/jcs.204321 |
| Popis: | Gap junctions (GJs) assembled from connexin (Cx) proteins play a pivotal role in cell-to-cell communication by forming channels that connect the cytosols of adjacent cells. Connexin 43, the best-studied Cx, is ubiquitously expressed in vertebrates. While phosphorylation is known to regulate multiple aspects of GJ function, much less is known about the role ubiquitination plays in these processes. Here we show by using ubiquitination-type specific antibodies and Cx43 lysine (K) to arginine (R) mutants that a portion of Cx43 in GJs can become K63-polyubiquitinated on K264 and K303. Relevant Cx43 K/R mutants assembled significantly larger GJ plaques, exhibited much longer protein half-lives and were internalization impaired. Interestingly, ubiquitin-deficient Cx43 mutants accumulated as hyper-phosphorylated polypeptides in the plasma membrane, suggesting that K63-polyubiquitination may be triggered by phosphorylation. Phospho-specific Cx43 antibodies revealed that upregulated phosphorylation affected serines 368, 279/282, and 255, well-known regulatory PKC and MAPK phosphorylation sites. Together, these novel findings suggest that upon internalization, some Cx43 in GJs becomes K63-polyubiquitinated, ubiquitination is critical for GJ internalization, and that K63-polyubiquitination may be induced by Cx phosphorylation.Summary StatementHere we show that connexin 43 in gap junctions becomes K63-poly ubiquitinated on lysines 264 and 303 and its requirement for gap junction endocytosis. These novel findings significantly contribute to our understanding of GJ turnover and patho-/physiology.Abbreviations usedAGJannular gap junctionAMSHassociated molecule with the SH3 domain of STAMCMEclathrin-mediated endocytosisCxConnexinCx43Connexin 43DUBdeubiquitinaseGJgap junctionMonoUbmonoubiquitinNedd4-1neural precursor cell expressed developmentally down-regulated protein 4-1PMplasma membranePolyUbpolyubiquitinTPA12-O-Tetradecanoylphorbol 13-AcetateTX-100Triton X-100RTroom temperatureUbubiquitin |
| Databáze: | OpenAIRE |
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