Baitinger C, Alderton J, Poenie M, Schulman H, Steinhardt R A
Department of Pharmacology, Stanford University School of Medicine, California 94305-5332.
J Cell Biol. 1990 Nov;111(5 Pt 1):1763-73. doi: 10.1083/jcb.111.5.1763.
The role of multifunctional Ca2+/calmodulin-dependent protein kinase (CaM kinase) in nuclear envelope breakdown (NEB) was investigated in sea urchin eggs. The eggs contain a 56-kD polypeptide which appears to be a homologue of neuronal CaM kinase. For example, it undergoes Ca2+/calmodulin-dependent autophosphorylation that converts it to a Ca2(+)-independent species, a hallmark of multifunctional CaM kinase. It is homologous to the alpha subunit of rat brain CaM kinase. Autophosphorylation and substrate phosphorylation by the sea urchin egg kinase are inhibited in vitro by CaMK(273-302), a synthetic peptide corresponding to the autoinhibitory domain of the neuronal CaM kinase. This peptide inhibited NEB when microinjected into sea urchin eggs. Only one mAb to the neuronal enzyme immunoprecipitated the 56-kD polypeptide. Only this antibody blocked or significantly delayed NEB when microinjected into sea urchin eggs. These results suggest that sea urchin eggs contain multifunctional CaM kinase, and that this enzyme is involved in the control of NEB during mitotic division.
在海胆卵中研究了多功能钙/钙调蛋白依赖性蛋白激酶（CaM激酶）在核膜破裂（NEB）中的作用。这些卵含有一种56-kD的多肽，它似乎是神经元CaM激酶的同源物。例如，它会进行钙/钙调蛋白依赖性的自身磷酸化，从而将其转化为一种不依赖钙的形式，这是多功能CaM激酶的一个标志。它与大鼠脑CaM激酶的α亚基同源。海胆卵激酶的自身磷酸化和底物磷酸化在体外被CaMK(273 - 302)抑制，CaMK(273 - 302)是一种与神经元CaM激酶的自身抑制结构域相对应的合成肽。当将这种肽显微注射到海胆卵中时，它抑制了NEB。只有一种针对神经元酶的单克隆抗体能免疫沉淀这种56-kD的多肽。当将这种抗体显微注射到海胆卵中时，只有它能阻断或显著延迟NEB。这些结果表明海胆卵含有多功能CaM激酶，并且这种酶参与有丝分裂过程中NEB的控制。
