Protein phosphorylation signaling pathways involved in gut motility

Protein phosphorylation signaling pathways involved in gut motility encompass the biochemical cascades that regulate the contractile state of gastrointestinal smooth muscle cells (Sanders, 2008, PMID: 18463636). The central mechanism involves the phosphorylation of the 20-kDa regulatory light chain of myosin (MLC20) by myosin light chain kinase (MLCK), a process initiated by calcium-calmodulin complexes (Somlyo & Somlyo, 2003, PMID: 14506304). This is balanced by the dephosphorylation activity of myosin light chain phosphatase (MLCP). Additionally, regulatory pathways such as RhoA/Rho-associated protein kinase (ROCK) and Protein Kinase C (PKC)/CPI-17 modulate motility by inhibiting MLCP, a phenomenon known as calcium sensitization (Somlyo & Somlyo, 2003). These pathways are critical for normal peristalsis and are often dysregulated in motility disorders like irritable bowel syndrome (IBS), gastroparesis, and chronic intestinal pseudo-obstruction (Wood, 2008). Therapeutic strategies targeting these pathways, such as ROCK inhibitors or guanylate cyclase-C agonists like Linaclotide, aim to restore normal gut transit by modulating these phosphorylation events (Chedid et al., 2012, PMID: 22573192). However, targeting these ubiquitous signaling molecules presents challenges, particularly regarding tissue specificity and the risk of systemic side effects like hypotension due to vascular smooth muscle relaxation.

Other names

Smooth muscle contraction signalingMyosin light chain phosphorylation pathwayGI motility signaling cascadesCalcium sensitization pathway

Modulation of the phosphorylation state of the 20-kDa regulatory light chain of myosin (MLC20) through the activation or inhibition of kinases (e.g., MLCK, ROCK) and phosphatases (e.g., MLCP) to regulate smooth muscle contractility.