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Abstract

Smooth muscles are important constituents of vertebrate organisms that provide for contractile activity of internal organs and blood vessels. Basic molecular mechanism of both smooth and striated muscle contractility is the force-producing ATP-dependent interaction of the major contractile proteins, actin and myosin II molecular motor, activated upon elevation of the free intracellular Ca2+ concentration ([Ca2+](i)). However, whereas striated muscles display a proportionality of generated force to the [Ca2+](i) level, smooth muscles feature molecular mechanisms that modulate sensitivity of contractile machinery to [Ca2+](i). Phosphorylation of proteins that regulate functional activity of actomyosin plays an essential role in these modulatory mechanisms. This provides an ability for smooth muscle to contract and maintain tension within a broad range of [Ca2+](i) and with a low energy cost, unavailable to a striated muscle. Detailed exploration of these mechanisms is required to understand the molecular organization and functioning of vertebrate contractile systems and for development of novel advances for treating cardiovascular and many other disorders. This review summarizes the currently known and hypothetical mechanisms involved in regulation of smooth muscle Ca2+-sensitivity with a special reference to phosphorylation of regulatory proteins of the contractile machinery as a means to modulate their activity.

Structure, Properties, and Probable Physiological Role of Small Heat Shock Protein with Molecular Mass 20 kD (Hsp20, HspB6)

“…Due to the lack of space, we will not analyze either effects of phosphory lation and dephosphorylation of myosin light chains or the role of caldesmon (or calponin) in regulation of smooth muscle contraction. These problems are thor oughly described in a number of recently published reviews [17,25,30,37,52]. Let us analyze only the effect of Hsp20 on the regulation of smooth muscle contrac tion.…”

A Review of the Current State of Magnetic Force Microscopy to Unravel the Magnetic Properties of Nanomaterials Applied in Biological Systems and Future Directions for Quantum Technologies

“…Finally, phosphorylation also regulates DNA replication by the activation of proteins like the checkpoint kinase 1 (Chk1), which delays the cell cycle progression under replication stress conditions or as a response to DNA damage [ 152 ]. Furthermore, phosphorylation is not only crucial to regulate DNA replication but, also, to control the energy supply in the cellular and tissue metabolisms [ 153 ], the proper functioning of the immunological system [ 154 ], and the muscular contraction [ 155 ], among others. Recently, it was discovered that the impact of B on the ATP synthesis and subsequent phosphorylation process took place during DNA replication [ 156 ].…”