[Mg2+,ATP-DEPENDENT PLASMA MEMBRANE CALCIUM PUMP OF SMOOTH MUSCLE CELLS. II. REGULATION OF ACTIVITY].

Plasma membrane Ca2+-pump is one of key proteins, which takes part in Ca2+ exchange in smooth muscle cells. It has a lot of diverse functions from control of basal cytoplasmal Ca2+ concentration to regulation of proteins involved in Ca2+-dependent signal pathway. Ca2+ pump function is often dependent on the isoform or even form of alternative splicing.

[Mg2+, ATP-dependent plasma membrane calcium pump of smooth muscle cells. I. Structural organization and properties].

Tight control of cytoplasm Ca2+ concentration is essential in cell functioning. Changing of Ca2+ concentration is thorough in smooth muscle cells, because it determines relaxation/constraint process. One of key proteins which control Ca2+ concentration in cytoplasm is Mg2+, ATP-dependent plasma membrane calcium pump.

[Kinetics of inhibitory effect of calix[4]arene C-90 on activity of transporting plasma membrane Ca2+, Mg2+-ATPase of smooth muscle cells].

In experiments on the suspension of myometrium cell plasma membrane, processed by 0.1% digitonin, the inhibitory action of calix[4]arene C-90 (5,11,17,23-tetra(threeftor)methyl(phenilsulphonilimino)-methylamino-25,26,27,28-tetrapropoxy-calix[4]arene) on the activity of Ca2+,Mg2+-ATPase was investigated. The authors also examined the influence of calix[4]arene in different concentration on affinity of enzyme (Ca2,Mg2+-ATPase) for the ATP and ions of Mg and Ca, and its influence on cooperative effect and maximum velocity of ATP hydrolysis.

[Kinetic properties of calixarene C-90 action on the myometrial plasma membrane Ca2+,Mg2+-Atpase activity and on the Ca2+ concentration in unexcited cells of the myometrium].

Plasma membrane Ca2+,Mg2+-ATPase is an important element of general myometrium tonus control mechanism, which also makes a contribution to muscle tension relaxation after its contraction. Expiriments were done on the myometrial cell plasma membrane suspension, which was treated with 0.1% digitonin solution.

[Regulation of the mitochondrial ATP-sensitive potassium channel in rat uterus cells by ROS].

In previous study we demonstrated the presence of ATP-sensitive potassium current in the inner mitochondrial membrane, which was sensitive to diazoxide and glybenclamide, in mitochondria isolated from the rat uterus. This current was supposed to be operated by mitochondrial ATP-sensitive potassium channel (mitoK(ATP)). Regulation of the mitoK(ATP) in uterus cells is not studied well enough yet.