Gorenne I, Su X, Moreland R S
Department of Physiology, MCP/Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19146, USA.
Am J Physiol. 1998 Jul;275(1):H131-8. doi: 10.1152/ajpheart.1998.275.1.H131.
Caldesmon inhibits myosin ATPase activity; phosphorylation of caldesmon reverses the inhibition. The caldesmon kinase is believed to be mitogen-activated protein (MAP) kinase. MAP kinases are activated during vascular stimulation, but a cause-and-effect relationship between kinase activity and contraction has not been established. We examined the role of MAP kinase in contraction using PD-098059, an inhibitor of MAP kinase kinase (MEK). MAP kinase activity was assessed using an anti-active MAP kinase antibody and direct measurement of MAP kinase catalyzed phosphorylation of myelin basic protein, MBP-(95-98). MAP kinase phosphorylation, stimulated by histamine (50 microM) or phorbol 12,13-dibutyrate (PDBu, 0.1 microM), was inhibited by PD-098059 (100 microM). PD-098059 did not alter the sensitivity or the maximal level of force in smooth muscle stimulated by histamine or PDBu, nor did PD-098059 affect contraction of beta-escin-permeabilized tissue. Our data suggest that p44 and p42 MAP kinases are not involved in regulation of vascular smooth muscle contraction. These results do not, however, preclude a role for other isoforms of the MAP kinase family.
钙调蛋白抑制肌球蛋白ATP酶活性；钙调蛋白的磷酸化可逆转这种抑制作用。钙调蛋白激酶被认为是丝裂原活化蛋白（MAP）激酶。MAP激酶在血管刺激过程中被激活，但激酶活性与收缩之间的因果关系尚未确立。我们使用MAP激酶激酶（MEK）抑制剂PD - 098059研究了MAP激酶在收缩中的作用。使用抗活性MAP激酶抗体并直接测量MAP激酶催化的髓鞘碱性蛋白MBP - (95 - 98)的磷酸化来评估MAP激酶活性。组胺（50微摩尔）或佛波醇12,13 - 二丁酸酯（PDBu，0.1微摩尔）刺激引起的MAP激酶磷酸化被PD - 098059（100微摩尔）抑制。PD - 098059不会改变组胺或PDBu刺激的平滑肌中力的敏感性或最大水平，PD - 098059也不会影响β - 七叶皂苷渗透组织的收缩。我们的数据表明，p44和p42 MAP激酶不参与血管平滑肌收缩的调节。然而，这些结果并不排除MAP激酶家族其他亚型的作用。
