Mastering the Control of Cytosolic Calcium

Smooth Muscle Contraction

• Thick filaments in smooth muscle are composed of myosin.
• An increase in cytosolic Ca2+ triggers smooth muscle contraction by binding to calmodulin, which activates myosin light chain kinase, leading to phosphorylation of myosin and subsequent muscle contraction.
• The concentration of calcium in the cytosol of smooth muscle increases due to the release of calcium ions from the sarcoplasmic reticulum or influx of calcium through the plasma membrane.
• The increase in cytosolic calcium concentration allows for the binding of calcium to calmodulin, ultimately leading to muscle contraction.

Test your knowledge on the control of cytosolic calcium in smooth muscle. Learn about the composition of thick and thin filaments, sarcomeres, and the lack of striation in smooth muscle. Explore the similarities and differences with skeletal and cardiac muscle in regulating calcium levels.