Pharmacological Evidence for System-Dependent Involvement of Protein Kinase C Isoenzymes in Phorbol Ester-Suppressed Gap Junctional Communication

2001 ◽  
Vol 268 (2) ◽  
pp. 150-161 ◽  
Author(s):  
Véronique Cruciani ◽  
Trine Husøy ◽  
Svein-Ole Mikalsen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Gap Junctional Communication ◽  
Kinase C ◽  
Junctional Communication ◽  
Gap Junctional

scholarly journals Protein kinase C spatially and temporally regulates gap junctional communication during human wound repair via phosphorylation of connexin43 on serine368

2004 ◽  
Vol 167 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Theresa S. Richards ◽  
Clarence A. Dunn ◽  
William G. Carter ◽  
Marcia L. Usui ◽  
John E. Olerud ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Wound Repair ◽  
Time Course ◽  
Phosphorylation Site ◽  
Primary Human Keratinocytes ◽  
Gap Junctional Communication ◽  
Kinase C ◽  
Junctional Communication ◽  
Gap Junctional

Phosphorylation of connexin43 (Cx43) on serine368 (S368) has been shown to decrease gap junctional communication via a reduction in unitary channel conductance. Examination of phosphoserine368 (pS368) in normal human skin tissue using a phosphorylation site–specific antibody showed relatively even distribution throughout the epidermal layers. However, 24 h after wounding, but not at 6 or 72 h, pS368 levels were dramatically increased in basal keratinocytes and essentially lost from suprabasal layers adjacent to the wound (i.e., within 200 μm of it). Scratch wounding of primary human keratinocytes caused a protein kinase C (PKC)-dependent increase in pS368 in cells adjacent to the scratch, with a time course similar to that found in the wounds. Keratinocytes at the edge of the scratch also transferred dye much less efficiently at 24 h, in a manner dependent on PKC. However, keratinocyte migration to fill the scratch required early (within <6 h) gap junctional communication. Our evidence indicates that PKC-dependent phosphorylation of Cx43 at S368 creates dynamic communication compartments that can temporally and spatially regulate wound healing.

scholarly journals Lysophosphatidic acid inhibits gap-junctional communication and stimulates phosphorylation of connexin-43 in WB cells: possible involvement of the mitogen-activated protein kinase cascade

1994 ◽  
Vol 303 (2) ◽  
pp. 475-479 ◽  
Author(s):  
C S T Hill ◽  
S Y Oh ◽  
S A Schmidt ◽  
K J Clark ◽  
A W Murray
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Phorbol Ester ◽  
Connexin 43 ◽  
Mitogen Activated Protein Kinase ◽  
Western Blots ◽  
Gap Junctional Communication ◽  
Junctional Communication ◽  
Mitogen Activated Protein ◽  
Gap Junctional

Lysophosphatidic acid (LPA) was shown to be a powerful inhibitor of gap-junctional communication between cultured rat liver WB cells, as determined by the transfer of Lucifer Yellow, with 50% inhibition obtained at about 0.3 microM LPA. Inhibition of communication was rapid (5 min) and was maintained for at least 80 min. After incubation for 3 h with LPA, communication competence was partially restored and dye transfer was refractory to further addition of LPA. Communication in LPA-refractory cells retained sensitivity to inhibition by phorbol ester and by epidermal growth factor (EGF). LPA-induced inhibition was associated with phosphorylation of connexin-43 protein, as detected by slower migration of the protein detected on Western blots, which could be eliminated by incubation of samples with alkaline phosphatase. A close correspondence was observed between the time- and dose-dependency of LPA effects on communication and the induction of mitogen-activated protein kinase (MAP kinase). Activation of both the 42 kDa and 44 kDa subspecies were confirmed by mobility shifts on Western blots using an anti-(MAP kinase R1) (erk 1-III) antibody and by fractionation on Mono Q columns. Cells pretreated with phorbol ester for 24 h were insensitive to phorbol ester inhibition of communication or activation of MAP kinase, but retained their sensitivity to LPA. The results indicate that LPA initiates the activation of protein kinase cascades in WB cells that are probably independent of protein kinase C and identifies connexin-43 as one substrate for the activated kinases.

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