Abstract：
Myoblast differentiation is essential for the formation of skeletal muscle myofibers. Profilin1 (Pfn1) has been identified as an actin-associated protein, and has been shown to be critically important to cellular function. Our previous study found that PFN1 may inhibit the differentiation of bovine skeletal muscle satellite cells, but the underlying mechanism is not known. Here, we confirmed that PFN1 negatively regulated the myogenic differentiation of bovine skeletal muscle satellite cells. Immunoprecipitation assay combined with mass spectrometry showed that Cdc42 was a binding protein of PFN1. Cdc42 could be activated by PFN1 and could inhibit the myogenic differentiation like PFN1. Mechanistically, activated Cdc42 increased the phosphorylation level of p2l-activated kinase (PAK), which further activated the phosphorylation activity of c-Jun N-terminal kinase (JNK), whereas PAK and JNK are inhibitors of myogenic differentiation. Taken together, our results reveal that PFN1 is a repressor of bovine myogenic differentiation, and provide the regulatory mechanism.
摘要：
成肌细胞分化对骨骼肌肌纤维的形成至关重要。Profilin1（Pfn1）已被鉴定为肌动蛋白相关蛋白，并已被证明对细胞功能至关重要。我们之前的研究发现，PFN1可能抑制牛骨骼肌卫星细胞的分化，但潜在的机制尚不清楚。这里,我们证实PFN1负调控牛骨骼肌卫星细胞的成肌分化。免疫沉淀结合质谱分析显示Cdc42是PFN1的结合蛋白。Cdc42可被PFN1激活，并能像PFN1一样抑制成肌分化。机械上,激活的Cdc42增加了p2l激活的激酶（PAK）的磷酸化水平，进一步激活c-Jun氨基末端激酶（JNK）的磷酸化活性，而PAK和JNK是肌源性分化的抑制剂。一起来看,我们的结果表明，PFN1是牛成肌分化的阻遏物，并提供监管机制。
