MAP kinases p38 and JNK are activated by the steroid hormone 1α,25(OH)2-vitamin D3 on the C2C12 muscle cell line
MAP kinases p38 and JNK are activated by the steroid hormone 1α,25(OH)2-vitamin D3 on the C2C12 muscle cell line
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DOI：
10.1002/jcb.20639
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发表时间：
2006-03-01
影响因子：
4
通讯作者：
Boland, R
中科院分区：
文献类型：
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作者：
Buitrago, CG;Ronda, AC;Boland, R
在鸡骨骼肌细胞的原代培养中，我们先前证明了维生素D的激素活性形式1α，25(OH)(2)-维生素D-3[1α，25(OH)(2)D-3]可以增加细胞外信号调节的丝裂原激活蛋白(MAP)激动子亚型ERK1和ERK2的磷酸化和活性，随后它们移位到细胞核并参与DNA合成刺激。在这项研究中，我们发现MAP激酶超家族的其他成员也被激素激活。利用肌肉细胞系C2C12，我们发现1α，25(OH)(2)D-3在1min内能磷酸化并增强p38MAPK的活性。直接上游丝裂原活化蛋白激酶3/6(MKK3/MKK6)也被激素磷酸化，提示它们参与了p38的激活。1α，25(OH)(2)D-3能够去磷酸化/激活C2C12细胞中普遍存在的胞浆酪氨酸激酶c-Src，用特定的抑制剂研究表明，Src参与了激素诱导的p38激活。重要的是，在C2C12中诱导的1α，25(OH)(2)D-3以p38激酶激活依赖的方式刺激有丝分裂原激活的蛋白激酶激活蛋白激酶2(MAPKAP-Kinase 2)和随后的热休克蛋白27(HSP27)的磷酸化。用p38抑制剂SB203580处理可阻断激素引起的p38磷酸化，并抑制其下游底物的磷酸化。1α，25(OH)(2)D-3也促进c-jun氨基末端蛋白激酶(JNK 1/2)的磷酸化，反应迅速(0.5-1min)，在生理剂量1α，25(OH)(2)D-3(1 NM)时达到最大磷酸化。ERK-1/2、p38和JNK-1/2在激素调节肌肉细胞增殖和分化中的相对作用及其相互关系仍有待确定。
In chick skeletal muscle cell primary cultures, we previously demonstrated that 1 alpha,25(OH)(2)-vitamin D-3 [1 alpha,25(OH)(2)D-3], the hormonally active form of vitamin D, increases the phosphorylation and activity of the extracellular signal-regulated mitogen-activated protein (MAP) kinase isoforms ERK1 and ERK2, their subsequent translocation to the nucleus and involvement in DNA synthesis stimulation. In this study, we show that other members of the MAP kinase superfamily are also activated by the hormone. Using the muscle cell line C2C12 we found that 1 alpha,25(OH)(2)D-3 within 1 min phosphorylates and increases the activity of p38 MAPK. The immediately upstream mitogen-activated protein kinase kinases 3/6 (MKK3/MKK6) were also phosphorylated by the hormone suggesting their participation in p38 activation. 1 alpha,25(OH)(2)D-3 was able to dephosphorylate/activate the ubiquitous cytosolic tyrosine kinase c-Src in C2C12 cells and studies with specific inhibitors imply that Src participates in hormone induced-p38 activation. Of relevance, 1 alpha,25(OH)(2)D-3 induced in the C2C12 line the stimulation of mitogen-activated protein kinase activating protein kinase 2 (MAPKAP-kinase 2) and subsequent phosphorylation of heat shock protein 27 (HSP27) in a p38 kinase activation-dependent manner. Treatment with the p38 inhibitor, SB203580, blocked p38 phosphorylation caused by the hormone and inhibited the phosphorylation of its downstrean substrates. 1 alpha,25(OH)(2)D-3 also promotesthe phosphorylation of c-jun N-terminal protein kinases (JNK 1/2), the response is fast (0.5-1 min) and maximal phosphorylation of the enzyme is observed at physiological doses of 1 alpha,25(OH)(2)D-3 (1 nM). The relative contribution of ERK-1/2, p38, and JNK-1/2 and their interrelationships in hormonal regulation of muscle cell proliferation and differentiation remain to be established.