Ohtsuki T, Jaffe H, Brenner M, Azzam N, Azzam R, Frerichs K U, Hallenbeck J M
Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-4128, USA.
J Cereb Blood Flow Metab. 1998 Sep;18(9):1040-5. 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.
哺乳动物的冬眠是一种对脑血流量严重减少的自然耐受状态。由于蛋白质酪氨酸磷酸化被认为参与了对潜在细胞损伤性刺激的抗性发展，我们使用针对磷酸酪氨酸部分的免疫印迹法来分析冬眠和非冬眠地松鼠各种组织的提取物。在脑中检测到一种单一的、冬眠特异性磷蛋白，但在任何其他测试组织中均未检测到。这种蛋白被命名为pp98以反映其表观分子量，它分布于整个大脑，并与细胞膜部分相关联。该蛋白的存在与冬眠状态紧密相关；在与冬眠动物处于相同低温环境下同时检测的动物中不存在，在一次冬眠期间（测试时间为1至14天）存在，并且在从冬眠苏醒后1小时内消失。pp98与冬眠状态的紧密关联、其在细胞膜中的存在以及膜磷酸酪氨酸蛋白的已知特性表明，它可能转导一种信号，以适应地松鼠冬眠所特有的氧气和葡萄糖供应有限以及细胞低温的情况。
