Figure 4.

Protein effectors of arterial smooth muscle contraction and dilation. Simplified representation of proteins and protein pathways involved in vascular smooth muscle contraction. Protein effectors present in our arterial database are indicated in italics and are listed in Table 1. It should be noted that while protein effectors of vascular smooth muscle relaxation (in particular, K⁺ channels, PMCAs, Na⁺/Ca²⁺ exchanger, and SERCAs) are present in this cartoon diagram, they are not in their activated states. ADP, adenosine diphosphate; ATP, adenosine triphosphate; Ca²⁺, calcium; CaM, calmodulin; G, G protein; LC20 (or MYL12B), myosin 20 kDa light chain; LC20.P (or MYL12B.P), phosphorylated myosin 20 kDa light chain; MLCK (or MYLK), myosin light-chain kinase; MLCP, myosin light-chain phosphatase; NO, nitric oxide; PLC, phospholipase C; PIP₂, phosphatidylinositol 4,5-bisphosphate; PKC, protein kinase C; PMCAs, plasma membrane calcium ATPases; ROCCs, receptor-operated calcium channels; SERCAs, smooth endoplasmic reticulum calcium ATPases; SOCCs, store-operated calcium channels; VGCCs, voltage-gated calcium channels. Inspired from Horowitz et al¹⁹ with permission from last author (KGM).