Phosphorylation of Gap Junction Proteins

描述（由申请人提供）：在脊椎动物中，间隙连接由连接蛋白家族的蛋白质组成，该家族在人类中包含大约20个成员。离子、氨基酸、核苷酸、其他代谢物和一些次级信使（如钙、cAMP、cGMP、IP3）很容易通过间隙连接，而大分子则被排除在外。GJC在许多细胞过程中起着至关重要的作用，包括控制细胞增殖、胚胎发育、细胞分化以及在静止细胞中协调各种稳态细胞功能。间隙连接蛋白connexin43 （Cx43）通过磷酸化及其与其他蛋白的相互作用受到调节。这一建议的重点是这两个调控过程在静止期间发挥的作用，以及它们如何随着增殖而变化。连接蛋白磷酸化可以调节间隙连接通讯（GJC）的水平。Cx43蛋白的胞质c端区有多个丝氨酸残基磷酸化。大量证据表明GJC在细胞周期中发生变化，并且我们有证据表明细胞在从静止到细胞周期的转变过程中会改变Cx43的磷酸化。我们假设Cx43磷酸化改变了与Cx43相互作用的蛋白质，并以细胞周期阶段特异性的方式改变Cx43运输、组装、门控和周转的动力学，从而影响细胞迁移和增殖等重要的生物过程。这项研究的重要性体现在连接蛋白定位和GJC的变化与伤口愈合过程中细胞增殖和迁移的精细控制以及癌变过程中生长控制的丧失之间的联系。我们假设Cx43磷酸化的变化以一种影响细胞功能的方式与这些过程相关。

DESCRIPTION (provided by applicant): In vertebrates, gap junctions are composed of proteins from the connexin family which contains approximately 20 members in humans. Ions, amino acids, nucleotides, other metabolites and some secondary messengers (e.g., calcium, cAMP, cGMP, IP3) readily pass through gap junctions while macromolecules are excluded. GJC is critically important in many cell processes, including control of cell proliferation, embryonic development, cell differentiation and the coordination of a variety of homeostatic cellular functions in quiescent cells. The gap junction protein connexin43 (Cx43) is regulated via phosphorylation and its interactions with other proteins. This proposal focuses on the role that these two regulatory processes play during quiescence and how they change with proliferation. Connexin phosphorylation can modulate the levels of gap junctional communication (GJC). Cx43 is phosphorylated at multiple serine residues found in the cytoplasmic, C-terrninal region of the protein. Extensive evidence indicates that GJC changes during the cell cycle, and we have evidence that cells change their Cx43 phosphorylation as they transition from quiescence through the cell cycle. We hypothesize that Cx43 phosphorylation alters the proteins that interact with Cx43 and can change the kinetics of Cx43 trafficking, assembly, gating, and turnover in a cell cycle stage-specific manner that affects important biological processes such as cell migration and proliferation. The importance of this research is exemplified by the linkage of changes in connexin localization and GJC to the exquisite control of cellular proliferation and migration during wound healing and with a loss of growth control during carcinogenesis. We hypothesize that Cx43 phosphorylation changes are linked to these processes in a way that affects cellular function.