Casnellie J E, Gentry L E, Rohrschneider L R, Krebs E G
Proc Natl Acad Sci U S A. 1984 Nov;81(21):6676-80. doi: 10.1073/pnas.81.21.6676.
The lymphoma cell line LSTRA contains an elevated level of tyrosine protein kinase activity. It has been suggested that this elevated level of activity is due to the presence of a phosphoprotein with a molecular weight of 56,000 (pp56, formerly referred to as a 58,000-dalton protein). This paper describes the preparation of antibodies against pp56 through the use of a synthetic peptide that contains the sequence around the site of tyrosine phosphorylation in pp56, which is identical to the phosphorylation site in pp60src. These antipeptide antibodies specifically immunoprecipitated 32P-labeled pp56 from detergent extracts of LSTRA cells. In immunoblotting experiments, pp56 was the major antigen detected in the particulate fraction from LSTRA cells by the antipeptide antibodies. The antibodies were also used to show that the level of pp56 is greatly elevated in LSTRA cells. Incubation of the detergent extract of the particulate fraction from LSTRA cells with the antipeptide antibodies resulted in inhibition of most of the LSTRA cell tyrosine protein kinase activity. These results indicate that pp56 is the tyrosine protein kinase whose activity is elevated in LSTRA cells. This enzyme may be a member of the large family of protein kinases involved in the regulation of cell growth.
淋巴瘤细胞系LSTRA含有高水平的酪氨酸蛋白激酶活性。有人提出，这种活性水平的升高是由于存在一种分子量为56,000的磷蛋白（pp56，以前称为58,000道尔顿的蛋白）。本文描述了通过使用一种合成肽制备抗pp56抗体的方法，该合成肽包含pp56中酪氨酸磷酸化位点周围的序列，该序列与pp60src中的磷酸化位点相同。这些抗肽抗体从LSTRA细胞的去污剂提取物中特异性免疫沉淀32P标记的pp56。在免疫印迹实验中，pp56是抗肽抗体在LSTRA细胞颗粒部分中检测到的主要抗原。这些抗体还用于表明LSTRA细胞中pp56的水平大大升高。将LSTRA细胞颗粒部分的去污剂提取物与抗肽抗体一起孵育导致大部分LSTRA细胞酪氨酸蛋白激酶活性受到抑制。这些结果表明pp56是其活性在LSTRA细胞中升高的酪氨酸蛋白激酶。这种酶可能是参与细胞生长调节的蛋白激酶大家族的一员。
