Figure 6 - Prostaglandin F2alpha (PGF2alpha)-induced protein kinase C (PKC) activation in LES tone and sustained contraction.

From the following article

Signal transduction in lower esophageal sphincter circular muscle

Piero Biancani and Karen M. Harnett

GI Motility online (2006)



We have shown (data in brown and green) that maintenance of LES tone is PKC-dependent, and mediated in part by Gq linked to phosphatidylinositol-specific phospholipase C (PI-PLC) and by Gi3 linked to phosphatidylcholine-specific phospholipase (PC-PLC). The interrupted gray arrows represent a proposed contractile pathway for maintenance of tone and sustained contraction.2 In sustained contraction receptors may activate G13, and initiate a cascade involving activation of a guanine nucleotide exchange factor (Rho-GEF), RhoA, Rho kinase, and phospholipase D (PLD). PLD produces diacylglycerol (DAG), which activates PKC, causing contraction and may potentiate PLD activation. PLD is also activated by an adenosine diphosphate (ADP) ribosylation factor (ARF)-dependent pathway. The mechanisms of activation of Rho kinase–induced activation of PLD and of ARF activation are unknown. (Source: Harnett et al.,3 with permission from the American Physiological Society.)

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