PKCµ promotes keratinocyte cell migration through Cx43 phosphorylation-mediated suppression of intercellular communication.

ABSTRACT

Downregulation of intercellular communication through suppression of gap junctional conductance is necessary during wound healing. Connexin 43 (Cx43), a prominent gap junction protein in skin, is downregulated following wounding to restrict communication between keratinocytes. Previous studies found that PKCµ, a novel PKC isozyme, regulates efficient cutaneous wound healing. However, the molecular mechanism by which PKCµ regulates wound healing remains unknown. We have identified that PKCµ suppresses intercellular communication and enhances cell migration in an in vitro wound healing model by regulating Cx43 containing gap junctions. PKCµ can directly interact with and phosphorylate Cx43 at S368, which leads to Cx43 internalization and downregulation. Finally, utilizing phosphomimetic and non-phosphorylatable S368 substitutions and gap junction inhibitors, we confirmed that PKCµ regulates intercellular communication and in vitro wound healing by controlling Cx43-S368 phosphorylation. These results define PKCµ as a critical regulator of Cx43 phosphorylation to control cell migration and wound healing in keratinocytes.