STRUCTURE-FUNCTION RELATIONSHIP OF PARATHYROID-HORMONE - ACTIVATION OF PHOSPHOLIPASE-C, PROTEIN KINASE-A AND KINASE-C IN OSTEOSARCOMA CELLS
STRUCTURE-FUNCTION RELATIONSHIP OF PARATHYROID-HORMONE - ACTIVATION OF PHOSPHOLIPASE-C, PROTEIN KINASE-A AND KINASE-C IN OSTEOSARCOMA CELLS
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DOI：
10.1210/en.130.1.29
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发表时间：
1992-01-01
期刊：
影响因子：
4.8
通讯作者：
CIVITELLI, R
中科院分区：
文献类型：
--
作者：
FUJIMORI, A;CHENG, SL;CIVITELLI, R
新近研究表明，PTH与其受体相互作用后，蛋白激酶A(PKA)和蛋白激酶C(PKC)均被激活。为了探讨PTH结构与蛋白激酶刺激的关系，我们分析了人工合成的PTH片段对大鼠骨肉瘤细胞UMR 106-01中PKA和PKC的影响。10(-7)M牛(B)PTH-(1-34)对PKA的激活在5min达到最大值(是对照组的2.7倍)，并在激素暴露后15min持续升高。等摩尔剂量的bpth-(2-34)也能刺激PKA，但效力较低(是对照的1.4倍)，而丙酰bpth-(2-34)[pbPTH-(2-34)]、bpth-(3-34)、[Tyr34]bpth-(7-34)酰胺[bpth-(7-34)]和bpth-(30-34)无效。另一方面，暴露于bpth-(1-34)后，PKC活性从胞浆到细胞膜的移位是短暂的，在1min达到峰值(是对照的1.9倍)，5min后恢复到基础水平。其他片段bpth-(2-34)、pbPTH-(2-34)、bpth-(3-34)和bpth-(7-34)对PKC也有活性，其相对效价分别为bpth-(1-34)的81%、67%、62%和51%，而bpth-(30-34)则没有活性。Bpth-(1-34)、bpth-(2-34)、pbPTH-(2-34)和bpth-(3-34)也可诱导1，4，5-三磷酸肌醇的产生，其效价分别为对照的1.6倍、1.6倍、1.5倍和1.6倍。Bpth-(7-34)和bpth-(30-34)都没有引起肌醇1，4，5-三磷酸产量的显著增加。这些结果表明，通过两种不同途径的PTH信号转导可能是分离的，而cAMP/PKA系统的激活需要氨基酸1和2，而磷脂酶-C/PKC系统耦合到激素N末端的较长区域。
Recent evidence indicates that after PTH interaction with its receptor, both protein kinase-A (PKA) and protein kinase-C (PKC) are activated. To investigate the relationship between PTH structure and protein kinase stimulation, we have analyzed the effects of synthetic PTH fragments on PKA and PKC in the rat osteogenic sarcoma cells, UMR 106-01. Activation of PKA by 10(-7) M bovine (b) PTH-(1-34) was maximal (2.7-fold of control) at 5 min and remained elevated 15 min after hormone exposure. bPTH-(2-34), at equimolar doses, also stimulated PKA, but with a lower potency (1.4-fold of control), whereas propionyl bPTH-(2-34) [pbPTH-(2-34)], bPTH-(3-34), [Tyr34]bPTH-(7-34) amide [bPTH-(7-34)], and bPTH-(30-34) were ineffective. On the other hand, translocation of PKC activity from the cytosol to the membrane after exposure to bPTH-(1-34) was transient, with a peak at 1 min (1.9-fold of control), and returned to basal levels after 5 min. Other fragments, bPTH-(2-34), pbPTH-(2-34), bPTH-(3-34), and bPTH-(7-34), were also active on PKC, with relative potencies of 81%, 67%, 62%, and 51% of bPTH-(1-34), respectively, whereas bPTH-(30-34) was inactive. bPTH-(1-34), bPTH-(2-34), pbPTH-(2-34), and bPTH-(3-34) also induced inositol 1,4,5-trisphosphate production, with a potency order of 1.6-, 1.6-, 1.5-, and 1.6-fold over the control value, respectively, thus indicating activation of phospholipase-C. Neither bPTH-(7-34) nor bPTH-(30-34) caused a statistically significant increase in inositol 1,4,5-trisphosphate production. These results demonstrate that PTH signal transduction through the two different pathways can be dissociated; while activation of the cAMP/PKA system requires amino acids 1 and 2, the phospholipase-C/PKC system is coupled to a longer domain of the hormone's N-terminus.