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首页> 外文期刊>Journal of Cellular Physiology >Homologous desensitization of ATP-stimulated mitogenesis: mechanism involves desensitization of arachidonic acid release and cAMP elevation but not the activation of protein kinase A.
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Homologous desensitization of ATP-stimulated mitogenesis: mechanism involves desensitization of arachidonic acid release and cAMP elevation but not the activation of protein kinase A.

机译:同源的脱敏ATP-stimulated有丝分裂发生:机制涉及脱敏花生四烯酸的释放和海拔但不激活的蛋白激酶。

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摘要

Prolonged incubation of quiescent 3T3, 3T6, and A431 cells with the P2Y purinoceptor agonists ATP, ADP, or AMPPNP reduced the mitogenic responses of target cells to a further challenge by these agonists, as measured by [3H]thymidine incorporation. The mitogenic desensitization was agonist-specific, for no effect was seen on DNA synthesis stimulated by epidermal growth factor, insulin, bombesin, 12-O-tetradecanoyl-phorbol-12 acetate (TPA), or adenosine. The desensitization was completely reversible, since after a 24 hr incubation in the absence of ATP, the cells responded fully to the mitogenic action of ATP. The presence of a low level of cycloheximide blocked recovery, suggesting that down-regulation of the P2Y receptor may have occurred during desensitization. In Swiss 3T3 cells, stimulation of DNA synthesis occurs predominantly by activation of arachidonic acid release, followed by its oxidation to prostaglandin E2 and stimulation of adenylyl cyclase. Interestingly, prolonged preincubation with ATP produced a similar degree of desensitization of DNA synthesis and of ATP-dependent arachidonic acid release and cAMP accumulation. Furthermore, this was true for both wild type cells and mutants with a defective cAMP-dependent protein kinase (PKA). We conclude that homologous desensitization is likely due to uncoupling of the P2Y purinoceptor from phospholipase A2, and this process does not require activation of protein kinase A.
机译:长时间静止3 t3的孵化,3 t6,A431细胞和P2Y purinoceptor受体激动剂ATP、ADP或AMPPNP减少了促有丝分裂的反应的靶细胞进一步的挑战通过这些受体激动剂,以[3 h]胸苷合并。agonist-specific,没有出现在DNA的影响合成刺激表皮生长因子,胰岛素,蛙皮素,12-O-tetradecanoyl-phorbol-12醋酸(TPA)或腺苷。是完全可逆的,因为24小时后孵化在ATP的缺失,细胞反应完全ATP的促有丝分裂的作用。低水平的环己酰亚胺的存在阻止了复苏,表明下调P2Y受体的可能发生脱敏。DNA合成的发生主要由激活花生四烯酸的释放,紧随其后通过前列腺素E2和氧化腺苷酸环化酶的刺激。长期与ATP产生预孵化相似程度的脱敏的DNA合成和ATP-dependent花生四烯酸释放和营地积累。对突变体和野生型细胞吗有缺陷的cAMP-dependent蛋白激酶(PKA)。脱敏可能由于解偶联从磷脂酶A2的P2Y purinoceptor,这个过程不需要激活蛋白激酶。

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