Figure 6 - Prostaglandin F2 (PGF2)-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)
doi:10.1038/gimo24
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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