Figure 2 : Signal transduction pathways leading to smooth muscle contraction. 

Abbreviations: cGKI: cGMP-dependent protein kinases, cGMP: cyclic guanosine onophosphate, ET-1: endothelin-1, 5-HT: 5-hydroxytryptamine (serotonin), GAP: GTPase
activating proteins, GEF: guanine nucleotide exchange factors, Gq/11: members of the Gq/111 subfamily of heterotrimeric G proteins with α, β, γ subunits, IP3: inositol 1,4,5-triphosphate, MLCK: myosin light chain kinase, MLCP: myosin light chain phosphatase, MYPT-1: myosin phosphatase target subunit 1, PIP2: phosphatidylinositol 4,5-bisphosphatase, PLCβ: phospholipase Cβ isoform, PS19: phosphoserine at position 19 of LC20.

Archavlis et al.Journal of Pharmaceutical Technology and Drug Research  2013 2:18DOI : 10.7243/2050-120X-2-18