Signaling from nucleotide receptors to protein kinase cascades in astrocytes.
In the CNS, extracellular ATP can function as an excitatory neurotransmitter as well as a trophic factor. These short-term and long-term actions are mediated by nucleotide receptors. Extracellular ATP can also act as a co-mitogen in conjunction with polypeptide growth factors such as basic fibroblast growth factor (FGF2). Cellular proliferation, differentiation and survival are regulated by signaling cascades composed of protein kinases, including extracellular signal regulated protein kinase (ERK) and protein kinase B (also called Akt). Here we summarize recent studies on nucleotide receptor signaling to ERK and Akt in astrocytes and the role of protein kinase cascades in mediating the trophic actions of extracellular ATP, alone or together with FGF2. Because extracellular ATP and FGF2 contribute to the hyperplastic and hypertrophic response of astrocytes to CNS injuries, an understanding of their protein kinase signaling mechanisms may lead to novel therapeutic approaches for neurological conditions that involve gliosis and the generation of reactive astrocytes, such as trauma, stroke, seizure and neurodegenerative and demyelinating disorders.
Neary
Joseph T
JT
Research Service, Miami VA Medical Center, Department of Pathology, University of Miami School of Medicine, Miami, FL 33125, USA. jneary@med.miami.edu
Kang
Yuan
Y
Shi
You-Fang
YF
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D001253:Astrocytes / Q000201:enzymology* / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000502:physiology; D006801:Humans; D009711:Nucleotides / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D020196:Trauma, Nervous System / Q000473:pathology / Q000503:physiopathology
D009711:Nucleotides; D011956:Receptors, Cell Surface; D016222:Fibroblast Growth Factor 2; D000255:Adenosine Triphosphate; D011494:Protein Kinases