Pryzwansky K B, Merricks E P
Department of Pathology, University of North Carolina, Chapel Hill, North Carolina 27599-7525, USA.
Mol Biol Cell. 1998 Oct;9(10):2933-47. doi: 10.1091/mbc.9.10.2933.
In neutrophils activated to secrete with formyl-methionyl-leucyl-phenylalanine, intermediate filaments are phosphorylated transiently by cyclic guanosine monophosphate (cGMP)-dependent protein kinase (G-kinase). cGMP regulation of vimentin organization was investigated. During granule secretion, cGMP levels were elevated and intermediate filaments were transiently assembled at the pericortex to areas devoid of granules and microfilaments. Microtubule and microfilament inhibitors affected intermediate filament organization, granule secretion, and cGMP levels. Cytochalasin D and nocodazole caused intermediate filaments to assemble at the nucleus, rather than at the pericortex. cGMP levels were elevated in neutrophils by both inhibitors; however, with cytochalasin D, cGMP was elevated earlier and granule secretion was excessive. Nocodazole did not affect normal cGMP elevations, but specific granule secretion was delayed. LY83583, a guanylyl cyclase antagonist, inhibited granule secretion and intermediate filament organization, but not microtubule or microfilament organization. Intermediate filament assembly at the pericortex and secretion were partially restored by 8-bromo-cGMP in LY83583-treated neutrophils, suggesting that cGMP regulates these functions. G-kinase directly induced intermediate filament assembly in situ, and protein phosphatase 1 disassembled filaments. However, in intact cells stimulated with formyl-methionyl-leucyl-phenylalanine, intermediate filament assembly is focal and transient, suggesting that vimentin phosphorylation is compartmentalized. We propose that, in addition to changes in microfilament and microtubule organization, granule secretion is also accompanied by changes in intermediate filament organization, and that cGMP regulates vimentin filament organization via activation of G-kinase.
在用甲酰甲硫氨酰亮氨酰苯丙氨酸激活以进行分泌的中性粒细胞中，中间丝被环磷酸鸟苷（cGMP）依赖性蛋白激酶（G激酶）短暂磷酸化。研究了cGMP对波形蛋白组织的调节作用。在颗粒分泌过程中，cGMP水平升高，中间丝在皮质周围短暂组装到无颗粒和微丝的区域。微管和微丝抑制剂影响中间丝组织、颗粒分泌和cGMP水平。细胞松弛素D和诺考达唑导致中间丝在细胞核而非皮质周围组装。两种抑制剂均使中性粒细胞中的cGMP水平升高；然而，使用细胞松弛素D时，cGMP升高更早且颗粒分泌过多。诺考达唑不影响正常的cGMP升高，但特异性颗粒分泌延迟。鸟苷酸环化酶拮抗剂LY83583抑制颗粒分泌和中间丝组织，但不影响微管或微丝组织。在LY83583处理的中性粒细胞中，8-溴-cGMP部分恢复了皮质周围的中间丝组装和分泌，表明cGMP调节这些功能。G激酶直接在原位诱导中间丝组装，而蛋白磷酸酶1使丝解聚。然而，在用甲酰甲硫氨酰亮氨酰苯丙氨酸刺激的完整细胞中，中间丝组装是局部的且短暂的，表明波形蛋白磷酸化是分隔的。我们提出，除了微丝和微管组织的变化外，颗粒分泌还伴随着中间丝组织的变化，并且cGMP通过激活G激酶来调节波形蛋白丝的组织。
