Nakamura Y, Takeda M, Angelides K J, Tanaka T, Tada K, Nishimura T
Department of Neuropsychiatry, Osaka University Medical School, Japan.
Biochem Biophys Res Commun. 1990 Jun 15;169(2):744-50. doi: 10.1016/0006-291x(90)90394-3.
The effect of phosphorylation by cyclic AMP dependent protein kinase on the assembly of the core-forming 68 KDa neurofilament subunit protein (NF-L) was studied in vitro by fluorescence energy transfer and electron microscopy. Phosphorylation of unassembled NF-L in a low ionic strength buffer by cyclic AMP dependent protein kinase led to the incorporation of 1-2 phosphate groups/mole protein. Assembly of this phosphorylated NF-L was inhibited significantly; compared to non-phosphorylated NF-L, the critical concentration of phosphorylated NF-L was raised by greater than 30-fold. Assembled NF-L filaments could also be phosphorylated by cyclic AMP dependent protein kinase indicating that the sites were accessible. Phosphorylation of NF-L in the filamentous state induced their disassembly. The results suggest that phosphorylation by cyclic AMP dependent protein kinase is a possible means to modulate the assembly state of NF-L.
通过荧光能量转移和电子显微镜在体外研究了环磷酸腺苷依赖性蛋白激酶磷酸化对核心形成68 kDa神经丝亚基蛋白（NF-L）组装的影响。在低离子强度缓冲液中，环磷酸腺苷依赖性蛋白激酶对未组装的NF-L进行磷酸化，导致每摩尔蛋白掺入1-2个磷酸基团。这种磷酸化的NF-L的组装受到显著抑制；与未磷酸化的NF-L相比，磷酸化的NF-L的临界浓度提高了30倍以上。组装好的NF-L丝也可以被环磷酸腺苷依赖性蛋白激酶磷酸化，这表明这些位点是可接近的。丝状状态的NF-L的磷酸化导致它们的解聚。结果表明环磷酸腺苷依赖性蛋白激酶磷酸化是调节NF-L组装状态的一种可能方式。
