Phosphorylation of connexin43 at MAPK, PKC or CK1 sites each distinctly alter the kinetics of epidermal wound repair

Abstract

The gap junction protein connexin 43 (Cx43) is a key player in wound healing, and inhibitors of Cx43, which speed epidermal wound healing, are currently in clinical trials. Here, we provide direct in vivo evidence that specific phosphorylation events on Cx43 change the physiological response during wound healing. Blocking phosphorylation, through mutation of serine residues in Cx43 at the protein kinase C (PKC) or casein kinase 1 (CK1) sites, significantly slowed the rate of wound closure in vivo and in vitro and resulted in a thicker epidermal layer after reepithelialization. Conversely, preventing Cx43 phosphorylation by mitogen-activated protein kinases (MAPKs) through mutation significantly increased the rate of wound closure in vivo. Defects in migration, but not proliferation, in all mutants were partially rescued in vitro by changing serine residues to aspartic or glutamic acid. These data prove that specific Cx43 phosphorylation events play an important role at different stages of wound healing. Thus, a clear physiological understanding of the spatiotemporal regulation of kinase activation and consequent effects on gap junctions could lead to a more targeted approach to modulating Cx43 expression during wound healing.

Platelet-Rich Plasma Modulates Gap Junction Functionality and Connexin 43 and 26 Expression During TGF-β1–Induced Fibroblast to Myofibroblast Transition: Clues for Counteracting Fibrosis

“…From a functional point of view, this may reflect the need for myofibroblasts to be coupled in response to stimuli that cause membrane potential alterations. However, myofibroblasts likely need to express a kind of Cx, such as Cx43, whose trafficking, half-life, and regulation (by phosphorylation) can be maximally modulated during differentiation to myofibroblast [84]. Corroborating this suggestion coming from electrophysiological records, here we found that myofibroblasts showed an increased expression of Cx43.…”

Cardiac macrophages prevent sudden death during heart stress

“…4g ). However, Cx43 is known to be phosphorylated at multiple sites by multiple signals 33 , 34 . To detect additional AREG-mediated pathways leading to Cx43 phosphorylation, we mutated the target phosphorylation sites on Cx43-GFP that correspond to the Akt, PKC, PKA, CK1, and MAPK signaling pathways.…”

Non-autonomous regulation of germline stem cell proliferation by somatic MPK-1/MAPK activity in C. elegans

“…Although speculative, an attractive idea is that somatic MPK-1A activity uses gap junctions to stimulate germline proliferation. In mice, ERK/MAPK phosphorylation of connexins modulates gap junction opening during epidermal wound healing ( Lastwika et al, 2019 ; Solan and Lampe, 2014 ). By analogy, MPK-1A could modulate gap junctions to allow unidentified proliferation-stimulatory small molecules entry into the germline.…”