Estradiol modulates the synapsins phosphorylation by various protein kinases in the rat brain under in vitro and in vivo conditions.

Synapsins are the neuronal phosphoproteins which play very important role in processes of synaptic neurotransmission. They are physiological substrates for Ser/Thr protein kinases. The reversible phosphorylation of synapsins may be modified by several compounds including steroid hormones.

Non-genomic effect of estradiol on plasma membrane calcium pump activity in vitro.

The aim of the presented study was to compare the effect of 17-beta-estradiol on the hydrolytic activity of plasma membrane calcium pump (PMCA) purified from excitable (rat cortical synaptosomes) and non-excitable (human erythrocytes) cells. Both types of cell membranes contained different composition of the PMCA isoforms. To elucidate if the hormone action could depend on structure of PMCA protein, we assayed the hormone effect on Ca(2+)-ATP-ases pretreated for 15 and 40 min with trypsin.

The isoform- and location-dependence of the functioning of the plasma membrane calcium pump.

The plasma membrane is a specialised multi-component structure with inter- and intracellular signalling functions. Ca2+ plays a crucial role in cellular physiology, and an ATP-driven plasma membrane calcium pump (PMCA) plays the greatest role in the maintenance of a low free Ca2+ concentration in the cytoplasm. The enzyme is coded by four separate genes (PMCA 1-4), and, due to alternative splicing, more than 20 variants can exist.

Calmodulin effect on purified rat cortical plasma membrane Ca(2+)-ATPase in different phosphorylation states.

The plasma membrane Ca(2+)-ATPase in neuronal tissue plays an important role in fine tuning of the intracellular Ca(2+) concentration. The enzyme exhibits a high degree of tissue specificity and is regulated by several mechanisms. Here we analysed the relationship between separate modes of Ca(2+)-ATPase regulation, i.

The activity of protein tyrosine kinases of rat heart after ischemia and reperfusion.

Background: Protein phosphorylation plays a very important role in the modulation of signal transduction in many tissues including heart. The activities of protein tyrosine kinases (PTKs) of the heart are rather low but PTKs in cardiac myocytes could be involved in many processes including necrosis, apoptosis, and inflammation. All of them lead to heart failure and are the result of such conditions as ischemia and reperfusion.