Alterations in hepatic protein kinase activity induced by triiodothyronine.
Alterations in hepatic protein kinase activity induced by triiodothyronine.
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三碘甲状腺原氨酸诱导的肝蛋白激酶活性的改变。
DOI：
10.1007/bf03348446
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发表时间：
1984
影响因子：
5.4
通讯作者：
Nakamura,H
中科院分区：
文献类型：
--
作者：
DeGroot,LJ;Rue,PA;Nakamura,H
以正常大鼠(N)为对照，分析了甲状腺功能减退(H)大鼠和经T3处理的甲状腺功能减退动物(T)大鼠肝脏制备的蛋白激酶(PK)活性的定量和定性变化。用DE-52纤维素柱对胞浆制剂进行层析，以评估蛋白激酶类型的质的变化。胞浆酶可分解成含有催化亚基的小组份I、含有1型全酶的组份II、含有不依赖于环AMP的PK的组份III和含有2型全酶的组份IV。还鉴定了一种以酪蛋白为底物的胞液激活酶。与N相比，H的1型全酶活性降低，其他质变不明显。用含0.3M KCl的溶剂提取核PKs。质变通过磷酸纤维素柱层析进行了评估，但现有的方法学没有给出个别PKs变化的可重复性证据。H在鱼精蛋白底物上的胞浆PK活性显著高于正常动物，而给予T3后，H水平在48h内逐渐降低至N水平。胞液中总PK的激活率在H组较高，T3组也降至N水平。这提示H大鼠肝细胞浆中可能存在较高的稳态环磷酸腺苷水平。以酪蛋白为底物的胞浆蛋白激酶在给药后48h内逐渐增加，从H水平到较高N水平。给药后48h达H值的110%。核PK的行为是完全不同的。以鱼精蛋白为底物的核PK反应在给药后1-1/2小时内升高，5小时达对照的130%，48小时恢复正常水平。相反，以酪蛋白为底物的核PK反应在给药后1~1/2小时也升高，并在给药后48小时一直保持在对照组的110~115%。给予放线菌酮或氨甲酰亚胺可阻止核PK活性的早期变化。观察到的胞液PK的变化，包括T3诱导的1型酶的增加，激活率的降低，与鱼精蛋白活化的激酶的减少，以及与酪蛋白反应的酶数量的增加，发生在24-48小时，可能是对T3的一般代谢反应的一部分。核内PK与鱼精蛋白和酪蛋白反应的早期数量增加可能与先前发现的核蛋白磷酸化的早期变化有关。放线菌酮和α-Amanitin对这些变化的抑制表明，这些变化是继发于PK的新合成，然后PK被转移到细胞核。
Quantitative and qualitative alterations in protein kinase (PK) activity in preparations of rat liver from hypothyroid (H) and T3-treated hypothyroid animals (T) were analyzed in comparison to epzyme from normal (N) animals. Qualitative variations in type of protein kinase were assessed by chromatography of cytosol preparations on DE-52 cellulose columns. Cytosol kinases resolved into a small fraction I containing a catalytic subunit, fraction II containing a type 1 holoenzyme, fraction III containing a cyclic-AMP independent PK, and fraction IV containing a type 2 holoenzyme. A cytosolic kinase active with casein as substrate was also identified. In H the type 1 holoenzyme was reduced in comparison to N. There were no other qualitative changes. Nuclear PKs were extracted with solvents containing 0.3 M KCl. Qualitative changes were evaluated by chromatography on phosphocellulose columns, but available methodology did not give reproducible evidence of changes in individual PKs. H had significantly more cytosolic PK active with protamine substrate than did normal animals, and by administration of T3, the H level was reduced progressively over 48 h to the N level. The activation ratio of total PK in cytosol was higher in H, and was also reduced to the N level by T3administration. This suggests a higher steady state level of cyclic-AMP may be present in H rat liver cytosol. Cytosolic protein kinase reactive with casein as substrate increased gradually over 48 h after T3 administration from the H to the higher N level. It was significantly elevated to 110% of the H value by 48 h after T3administration. The behavior of nuclear PK was entirely different. Nuclear PK reactive with protamine as substrate was increased within 1–1/2 h after T3administration, reaching a peak of 130% of the control value at 5 h and returning to the normal level by48h. In contrast, nuclear PK reactive with casein as substrate also increased by 1–1/2 h after T3administration and remained elevated at 110–115% of the control value throughout 48 h after T3administration. The early changes in nuclear PK activity were prevented by administration of cycloheximide or or-amanitin. The observed changes in cytosolic PK, including the increment induced by T3in type 1 enzyme, reduction in the activation ratio, reduction in kinase active with protamine, and increase in the amount of enzyme reactive with casein, occurring at 24–48 h, presumably are part of the generalized metabolic response to T3. The early quantitative increment in nuclear PK reactive with protamine and with casein could be associated with the early changes in phosphorylation of nuclear proteins previously identified. Inhibition of the changes by cycloheximide and α-amanitin suggest that the changes are secondary to neosynthesis of PK, which is then translocated to nucleus.