ATG16L1 phosphorylation is oppositely regulated by CSNK2/casein kinase 2 and PPP1/protein phosphatase 1 which determines the fate of cardiomyocytes during hypoxia/reoxygenation
ATG16L1 phosphorylation is oppositely regulated by CSNK2/casein kinase 2 and PPP1/protein phosphatase 1 which determines the fate of cardiomyocytes during hypoxia/reoxygenation
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ATG16L1 磷酸化受到 CSNK2/酪蛋白激酶 2 和 PPP1/蛋白磷酸酶 1 的相反调节，决定缺氧/复氧期间心肌细胞的命运
DOI：
10.1080/15548627.2015.1060386
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发表时间：
2015-08-01
期刊：
影响因子：
13.3
通讯作者：
Zhang, Zhiyong
中科院分区：
文献类型：
--
作者：
Song, Huiwen;Pu, Jun;Zhang, Zhiyong
近期研究表明，ULK1和ATG13的磷酸化与去磷酸化与自噬活性相关。尽管ATG16L1通过影响自噬体的形成，对自噬诱导来说是绝对必需的，但其翻译后修饰情况仍不明确。在此，我们探究了ATG16L1磷酸化在心肌细胞自噬诱导中的调控机制及作用。我们发现ATG16L1是一种磷蛋白，因为在缺氧/复氧（H/R）过程中，在大鼠心肌细胞中检测到了ATG16L1的磷酸化。我们不仅证实酪蛋白激酶2（CSNK2）可使ATG16L1发生磷酸化，还确定了高度保守的丝氨酸139（Ser139）是CSNK2作用的关键磷酸化残基。我们进一步证实，ATG16L1以Ser139磷酸化依赖的方式与ATG12 - ATG5复合物相结合。与这一发现相符的是，CSNK2抑制剂会破坏ATG12 - ATG5 - ATG16L1复合物。重要的是，ATG16L1在Ser139位点的磷酸化是心肌细胞中H/R诱导自噬的原因，而自噬可保护心肌细胞免于凋亡。相反，我们确定野生型蛋白磷酸酶1（PPP1），而非无活性的突变体，可与ATG16L1相结合，并拮抗CSNK2介导的ATG16L1磷酸化。有趣的是，我们鉴定出ATG16L1 C末端尾部存在一个与PPP1结合的RVxF共有位点；该位点的突变会破坏其与ATG16L1的结合。值得注意的是，CSNK2也与PPP1相结合，但ATG16L1的缺失会削弱CSNK2与PPP1之间的相互作用。综上所述，这些数据表明ATG16L1是CSNK2和PPP1真正的生理性底物，这揭示了从CSNK2到自噬特异性ATG12 - ATG5 - ATG16L1复合物激活及自噬诱导之间新的分子联系。
Recent studies have shown that the phosphorylation and dephosphorylation of ULK1 and ATG13 are related to autophagy activity. Although ATG16L1 is absolutely required for autophagy induction by affecting the formation of autophagosomes, the post-translational modification of ATG16L1 remains elusive. Here, we explored the regulatory mechanism and role of ATG16L1 phosphorylation for autophagy induction in cardiomyocytes. We showed that ATG16L1 was a phosphoprotein, because phosphorylation of ATG16L1 was detected in rat cardiomyocytes during hypoxia/reoxygenation (H/R). We not only demonstrated that CSNK2 (casein kinase 2) phosphorylated ATG16L1, but also identified the highly conserved Ser139 as the critical phosphorylation residue for CSNK2. We further established that ATG16L1 associated with the ATG12-ATG5 complex in a Ser139 phosphorylation-dependent manner. In agreement with this finding, CSNK2 inhibitor disrupted the ATG12-ATG5-ATG16L1 complex. Importantly, phosphorylation of ATG16L1 on Ser139 was responsible for H/R-induced autophagy in cardiomyocytes, which protects cardiomyocytes from apoptosis. Conversely, we determined that wild-type PPP1 (protein phosphatase 1), but not the inactive mutant, associated with ATG16L1 and antagonized CSNK2-mediated phosphorylation of ATG16L1. Interestingly, one RVxF consensus site for PPP1 binding in the C-terminal tail of ATG16L1 was identified; mutation of this site disrupted its association with ATG16L1. Notably, CSNK2 also associated with PPP1, but ATG16L1 depletion impaired the interaction between CSNK2 and PPP1. Collectively, these data identify ATG16L1 as a bona fide physiological CSNK2 and PPP1 substrate, which reveals a novel molecular link from CSNK2 to activation of the autophagy-specific ATG12-ATG5-ATG16L1 complex and autophagy induction.