Stimulation of Tyrosine Phosphorylation of a Brain Protein by Hibernation

• Published in: Journal of cerebral blood flow and metabolism Vol. 18; no. 9; pp. 1040 - 1045
• Main Authors: Ohtsuki, Toshiho, Jaffe, Howard, Brenner, Michael, Azzam, Nabil, Azzam, Rita, Frerichs, Kai U., Hallenbeck, John M.
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.09.1998; Lippincott Williams & Wilkins
• Subjects: Animals; Biological and medical sciences; Brain - metabolism; Brain - physiology; Cold Climate; Fundamental and applied biological sciences. Psychology; Hibernation - physiology; Membrane Proteins - metabolism; Nerve Tissue Proteins - metabolism; Phosphorylation; Protein-Tyrosine Kinases - metabolism; Sciuridae - physiology; Signal Transduction - physiology; Thermoregulation. Hibernation. Estivation. Ecophysiology and environmental effects; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Ischemic tolerance; Tyrosine kinase; Membrane phosphotyrosine protein; Ground squirrel; Tyrosine; Phosphorylation; Ischemia; Animal; Hibernation; Plasma membrane; Immunoblotting assay; Tolerance; Exploration; Physiology; Localization
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1097/00004647-199809000-00014

Mammalian hibernation is a state of natural tolerance to severely decreased brain blood flow. As protein tyrosine phosphorylation is believed to be involved in the development of resistance to potentially cell-damaging insults, we used immunoblotting for the phosphotyrosine moiety to analyze extracts from various tissues of hibernating and nonhibernating ground squirrels. A single, hibernation-specific phosphoprotein was detected in the brain, but not in any other tissue tested. This protein, designated pp98 to reflect its apparent molecular weight, is distributed throughout the brain, and is associated with the cellular membrane fraction. The presence of the protein is tightly linked to the hibernation state; it is not present in contemporaneously assayed animals that are exposed to the same cold temperature as the hibernators, is present for the duration of a hibernation bout (tested from 1 to 14 days), and disappears within 1 hour of arousal from hibernation. The close association of pp98 with the hibernation state, its presence in cellular membranes, and the known properties of membrane phosphotyrosine proteins suggest that it may transduce a signal for adaptation to the limited availability of oxygen and glucose and low cellular temperature that characterizes hibernation in the ground squirrel.