Ganguli S, Hu L, Menke P, Collier R J, Gertler A
Indiana University School of Medicine, Terre Haute Center for Medical Education 47809, USA.
J Cell Physiol. 1996 May;167(2):251-60. doi: 10.1002/(SICI)1097-4652(199605)167:2<251::AID-JCP8>3.0.CO;2-O.
Intracellular kinases play important roles in signal transduction and are involved in the surface receptor-mediated regulation of cellular functions, including mitogenesis. In the present study, we examined the possible involvement of various protein kinases in the passage of a mitogenic signal from the cell surface to the nucleus of Nb2 cells, a rat nodal lymphoma cell line in which prolactin is a mitogen. Following a prolactin challenge, various kinase activities were monitored at short intervals in different cellular fractions over a 60 min period. Protein kinase C (PKC) activity in the cytosolic fraction rapidly declined to 50% of its original activity within the first 30 min, while PKC activity in the nuclear fractions increased sharply, reaching its highest level by 30 min following a prolactin challenge. There were also increases in both casein kinase and protein tyrosine kinase (PTK) activities in the nuclear fractions during the first 30 min following a prolactin challenge that paralleled PKC activity. The activities of all three kinases declined thereafter, reaching levels close to their respective basal values by 60 min following initiation of prolactin treatment. These observations suggest the possibility that multiple protein kinases may be involved in mitogenic signal transduction for prolactin in Nb2 cells.
细胞内激酶在信号转导中发挥重要作用，并参与表面受体介导的细胞功能调节，包括有丝分裂原的生成。在本研究中，我们检测了多种蛋白激酶在促有丝分裂信号从细胞表面传递至Nb2细胞（一种大鼠淋巴结淋巴瘤细胞系，其中催乳素是一种有丝分裂原）细胞核过程中可能的参与情况。在催乳素刺激后，在60分钟内每隔一段时间监测不同细胞组分中的各种激酶活性。胞质组分中的蛋白激酶C（PKC）活性在前30分钟内迅速降至其原始活性的50%，而核组分中的PKC活性急剧增加，在催乳素刺激后30分钟达到最高水平。在催乳素刺激后的前30分钟内，核组分中的酪蛋白激酶和蛋白酪氨酸激酶（PTK）活性也增加，与PKC活性平行。此后，这三种激酶的活性均下降，在催乳素处理开始后60分钟达到接近各自基础值的水平。这些观察结果提示，多种蛋白激酶可能参与Nb2细胞中催乳素的促有丝分裂信号转导。
