Tag Archives: rat brain

Ser-Thr phosphatases in the rat brain that dephosphorylate phospho-Ser(1291)-GluN2A subunit of glutamate receptor

R. R. Prabhu1,2

1P. G. Department of Biotechnology, Government Arts College, Thycaud P. O, Trivandrum, India;
2Rajiv Gandhi Centre for Biotechnology, Poojappura, Thycaud P. O, Trivandrum, India;
e-mail: ramyarprabhu@gmail.com

Received: 04 June 2023; Revised: 06 July 2023;
Accepted: 7 September 2023; Available on-line: 12 September 2023

N-methyl-D-aspartate receptors (NMDARs), are one of the major ionotropic glutamate receptors found in excitatory synapses which play a key role in glutamatergic synaptic transmission. The receptors are regulated by post translational modifications such as phosphorylation. One of the major receptor subunits is GluN2A which is likely to get phosphorylated in vitro at a putative site Ser1291. However, the regulation of phosphorylation of this site by kinases and phosphatases is not yet completely understood. In the present study, we have used the fusion constructs of GluN2A tagged with glutathione S-transferase (GST) as substrate for phosphorylation, purified calcium/calmodulin dependent protein kinase type II (CaMKII) and radioactive P32. We demonstrated that the site phosphorylated by αCaMKII on GluN2A was Ser1291 and that protein phosphatases 1, 2A and 2C were able to dephosphorylate this phospho-GST-GluN2A-Ser1291 in vitro. In the rat brain tissue post synaptic density and cytosolic fraction the major phosphatase responsible for dephosphorylating phospho-GluN2A-Ser1291 was protein phosphatase 1.

Plasminogen and its fragments in rat brain: a plausible role for astrocytes in angiostatin generation

A. A. Tykhomyrov1, V. S. Nedzvetsky2,3, C. A. Ağca3,
V. V. Korsa1, T. V. Grinenko1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Dnipropetrovsk National University, Dnipro, Ukraine;
3Bingöl University, Bingöl, Turkey;
e-mail: artem_tykhomyrov@ukr.net

The purpose of the present study was to examine the plasminogen localization and to detect levels of its fragments (angiostatins) in various regions of rat brain as well as to establish whether rat brain astrocytes could be involved in angiostatin production. It was shown immunohistochemically that plasminogen is distributed broadly in the various brain regions, with predominant expression in meningeal layer and IV, V, and VI layers or cerebral cortex, dentate gyrus, meningeal and Purkinje cells, molecular and granular layers of cerebellum, as well as vessel walls. Angiostatin polypeptides were detected by Western blot analysis mostly in the cerebral cortex and were represented by 50 and 40-30 kDa polypeptides. In the whole cell lysates from primary cultures of rat astrocytes, immunoreactive polypeptides with Mm ~ 92, 84, 65-60, 50, 40, 38-30 kDa, correspon­ding to native plasminogen and a variety of its truncated products, including angiostatin polypeptides, were revealed. Incubation of astrocytes with exogenous plasminogen resulted in gradual increasing levels of some plasminogen fragments, particularly 30 kDa protein. Moreover, this polypeptide appeared to be the single angiostatin released by astrocytes in vitro. We report here for the first time that astrocytes are one of the cell types in CNS that could be responsible for angiostatin formation and releasing.

Distribution of glial fibrillary acidic protein in different parts of the rat brain under cadmium exposure

Yu. P. Kovalchuk1, I. V. Prischepa1, U. Si2, V. S. Nedzvetsky1,
Y. G. Kot2, E. E. Persky2, G. A. Ushakova1

1Oles’ Honchar Dnepropetrovsk National University, Ukraine;
2V. N. Karazin  Kharkiv National University, Ukraine;
e-mail:  yulka.kovalchuk.5868152@mail.ru

The chronic effects of low doses of cadmium on the distribution of soluble and filament forms of glial fibrillary acidic protein (GFAP) and their polypeptide fragments in different parts of the rat brain were investigated. Obtained results showed dose-dependent effect of cadmium on the soluble form of GFAP and more pronounced effect on the filament form and composition of the polypeptide fragments of the protein in the rat brain. Prolonged intoxication by cadmium ions in a dose of 1.0 µg/kg of body weight induced a significant decrease in soluble GFAP and an increase in the filament form in the rat brain, pointing to the development of reactive astrogliosis and the risk of neurodegeneration.