van den IJssel P R, Overkamp P, Bloemendal H, de Jong W W
Department of Biochemistry, University of Nijmegen, Nijmegen, NL-6500 HB, The Netherlands.
Biochem Biophys Res Commun. 1998 Jun 18;247(2):518-23. doi: 10.1006/bbrc.1998.8699.
Three members of the small heat shock protein family, alphaA-, alphaB-crystallin, and HSP27, confer thermoresistance upon their overexpression in mammalian cells. Phosphorylation, in conjunction with the molecular chaperone-like activity of these small HSPs, is believed to be important for this in situ functional property. We here report the influence of heat shock and other kinds of stress on the phosphorylation of alphaA-, alphaB-crystallin, and HSP27 in stably transfected HeLa cells. It is observed that alphaB-crystallin becomes phosphorylated upon exposure to the same inducers as is HSP27, although to a lesser extent. In contrast, phosphorylation of alphaA-crystallin is very low upon heat stress and even absent when other stressors are used. This indicates that phosphorylation is not in all instances essential for the stress protective functioning of the various small HSPs.
小热休克蛋白家族的三个成员，αA-晶状体蛋白、αB-晶状体蛋白和热休克蛋白27（HSP27），在哺乳动物细胞中过表达时可赋予热耐受性。磷酸化与这些小热休克蛋白的分子伴侣样活性共同作用，被认为对这种原位功能特性很重要。我们在此报告热休克和其他类型应激对稳定转染的HeLa细胞中αA-晶状体蛋白、αB-晶状体蛋白和HSP27磷酸化的影响。观察到αB-晶状体蛋白在暴露于与HSP27相同的诱导剂时会发生磷酸化，尽管程度较小。相比之下，αA-晶状体蛋白在热应激时磷酸化水平非常低，而在使用其他应激源时甚至不存在磷酸化。这表明磷酸化并非在所有情况下都是各种小热休克蛋白应激保护功能所必需的。
