Calcium-dependent activation of Erk-1 and Erk-2 after hypo-osmotic astrocyte swelling
Abstract
The influence of hypo-osmotic cell swelling on the activity of the mitogen-activated protein (MAP) kinases Erk-1 and Erk-2 (where Erk stands for extracellular signal-regulated protein kinase) was studied in cultured rat astrocytes. Hypo-osmotic treatment led within 10 min to an increased activity of Erk-1 and Erk-2, which became maximal at 20 min and returned to the basal level within 60 min. Moreover, exposure to hypo-osmotic conditions induced a biphasic increase in cytosolic Ca2+ concentration ([Ca2+]i): a rapid peak-like increase was followed by a sustained plateau. The absence of extracellular Ca2+ completely abolished Erk activation as well as the plateau of the [Ca2+]i response after hypo-osmotic stimulation. Application of wortmannin and agents to elevate intracellular cAMP levels also completely blocked Erk activation but were without effect on the biphasic [Ca2+]i response to hypo-osmotic treatment of the cells, suggesting a role of PtdIns 3-kinase and the Ras/Raf pathway downstream of the calcium signal. Protein kinase C (PKC) and Ca2+/calmodulin (CaM)-dependent kinases are unlikely to play a role in the hypo-osmolarity-induced signalling towards MAP kinases, as revealed by the blockage of PKC and CaM kinases. Inhibi...Continue Reading
Citations
Influence of protein kinases on the osmosensitive release of taurine from cerebellar granule neurons
Related Concepts
Related Feeds
Astrocytes & Neurodegeneration
Astrocytes are important for the health and function of the central nervous system. When these cells stop functioning properly, either through gain of function or loss of homeostatic controls, neurodegenerative diseases can occur. Here is the latest research on astrocytes and neurodegeneration.
AKT Pathway
This feed focuses on the AKT serine/threonine kinase, which is an important signaling pathway involved in processes such as glucose metabolism and cell survival.
Astrocytes
Astrocytes are glial cells that support the blood-brain barrier, facilitate neurotransmission, provide nutrients to neurons, and help repair damaged nervous tissues. Here is the latest research.
Calcium & Bioenergetics
Bioenergetic processes, including cellular respiration and photosynthesis, concern the transformation of energy by cells. Here is the latest research on the role of calcium in bioenergetics.