Astrocyte process growth induction by actin breakdown.
Astrocyte process growth induction by actin breakdown.
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DOI：
10.1083/jcb.117.2.357
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发表时间：
1992-04
期刊：
影响因子：
--
通讯作者：
Shelanski ML
中科院分区：
文献类型：
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作者：
Baorto DM;Mellado W;Shelanski ML
cAMP 类似物如二丁酰 cAMP (dBcAMP) 已被证明可以诱导培养的原代星形胶质细胞中突起的形成。我们观察到该过程是通过伸长以及先前报道的细胞骨架元件周围细胞质的回缩而形成的。 dBcAMP 响应时发生的最显着的细胞骨架变化是肌动蛋白丝的重排，其特征是皮质 F-肌动蛋白染色的丧失以及肌动蛋白丝染色在突起尖端的出现。如果用二氢细胞松弛素 B 破坏皮质肌动蛋白丝，则会形成与 dBcAMP 诱导的过程类似的过程，表明皮质肌动蛋白网络的破坏是过程形成的关键步骤。响应 cAMP 的肌动蛋白丝网络重组伴随着肌球蛋白 (MLC) 调节轻链中磷酸盐掺入的减少。 MLC 激酶 (MLCK) 的两种选择性抑制剂 ML-9 和 KT5926，以及钙调蛋白拮抗剂 (W7)（也会抑制 MLCK 激活）均会诱导星形细胞过程生长，表明 MLCK 作为过程启动的控制点。我们还发现dBcAMP和ML-9均导致肌动蛋白解聚因子的磷酸盐含量降低，表明该蛋白和肌球蛋白轻链是肌动蛋白细胞骨架重组和过程生长的效应器。
cAMP analogues such as dibutyryl cAMP (dBcAMP) have been shown to induce the formation of processes in cultured primary astrocytes. We observe that the processes form by elongation as well as the previously reported retraction of cytoplasm around cytoskeletal elements. The most prominent cytoskeletal change that occurs in response to dBcAMP is a rearrangement of actin filaments characterized by a loss of cortical F- actin staining and the appearance of actin filament staining at the tips of the processes. If cortical actin filaments are disrupted with dihydrocytochalasin B, processes form that are similar to those induced by dBcAMP suggesting that the disruption of the cortical actin network is the pivotal step in process formation. Reorganization of the actin filament network in response to cAMP is accompanied by a decrease in phosphate incorporation into the regulatory light chain of myosin (MLC). Two selective inhibitors of MLC kinase (MLCK), ML-9 and KT5926, as well as a calmodulin antagonist (W7), which would also inhibit MLCK activation, all induce astrocytic process growth implicating MLCK as a control point in process initiation. We also found that dBcAMP and ML-9 both cause a decrease in the phosphate content of actin depolymerizing factor, suggesting that this protein and myosin light chain are the effectors of actin cytoskeleton reorganization and process growth.