Sanguedolce M V, Capo C, Bouhamdan M, Bongrand P, Huang C K, Mege J L
Laboratoire d'Immunologie, Hôpital de Sainte-Marguerite, Marseille, France.
J Immunol. 1993 Jul 1;151(1):405-14.
Protein tyrosine phosphorylations are involved in the proliferation and secretory responses of immune cells, but their role in phagocytes is poorly understood. The ability of unopsonized zymosan to induce protein tyrosine phosphorylations was investigated in human monocytes. The addition of zymosan to monocytes resulted in an increase in tyrosine phosphorylation of several endogenous proteins including 28-, 33-, 38-, 42-, 47-, 55- to 60-, 62-, 68-, 90-, 105-, 116-, and 120-kDa proteins; 55- to 60-kDa proteins were the predominant phosphoproteins. Moreover, we studied the effects of tyrphostin 23, a specific tyrosine kinase inhibitor, on stimulated tyrosine phosphorylations and early secretory responses of monocytes, i.e., arachidonic acid release and oxidative metabolism. We showed that tyrphostin inhibited zymosan-stimulated tyrosine phosphorylations and arachidonic acid release, but that it did not affect superoxide generation induced by zymosan. Zymosan binds mainly to CR3 receptor on human monocytes, and CR3 is devoid of intrinsic tyrosine kinase activity. It was predictable that zymosan stimulated a tyrosine kinase distal to the receptor or associated with it. We observed that PMA mimicked zymosan-induced tyrosine phosphorylations, thus suggesting that both agonists used a common transductional pathway implicating the serine/threonine kinase, protein kinase C. The antagonists of protein kinase C, sphingosine and calphostin C, inhibited zymosan-stimulated tyrosine phosphorylations. We suggest that, in human monocytes, zymosan-induced tyrosine phosphorylations are involved in cell responses such as the release of arachidonic acid, and that they require the sequential activation of protein kinase C and cellular protein tyrosine kinases.
蛋白质酪氨酸磷酸化参与免疫细胞的增殖和分泌反应，但其在吞噬细胞中的作用尚不清楚。我们研究了未调理的酵母聚糖在人单核细胞中诱导蛋白质酪氨酸磷酸化的能力。向单核细胞中添加酵母聚糖导致几种内源性蛋白质的酪氨酸磷酸化增加，包括28 kDa、33 kDa、38 kDa、42 kDa、47 kDa、55至60 kDa、62 kDa、68 kDa、90 kDa、105 kDa、116 kDa和120 kDa的蛋白质；55至60 kDa的蛋白质是主要的磷酸化蛋白。此外，我们研究了特异性酪氨酸激酶抑制剂 tyrphostin 23 对单核细胞刺激的酪氨酸磷酸化和早期分泌反应（即花生四烯酸释放和氧化代谢）的影响。我们发现tyrphostin抑制酵母聚糖刺激的酪氨酸磷酸化和花生四烯酸释放，但不影响酵母聚糖诱导的超氧化物生成。酵母聚糖主要与人单核细胞上的CR3受体结合，而CR3缺乏内在的酪氨酸激酶活性。可以预测，酵母聚糖刺激了受体远端或与其相关的酪氨酸激酶。我们观察到佛波酯（PMA）模拟了酵母聚糖诱导的酪氨酸磷酸化，因此表明这两种激动剂使用了涉及丝氨酸/苏氨酸激酶（蛋白激酶C）的共同转导途径。蛋白激酶C的拮抗剂鞘氨醇和钙泊三醇（calphostin C）抑制酵母聚糖刺激的酪氨酸磷酸化。我们认为，在人单核细胞中，酵母聚糖诱导的酪氨酸磷酸化参与细胞反应，如花生四烯酸的释放，并且它们需要蛋白激酶C和细胞蛋白酪氨酸激酶的顺序激活。
