Abstract：
Protein phosphorylation plays an important role in the signal transduction and is capable of regulation of cell activity. The death-associated protein kinase 1 (DAPK1), as a Ser/Thr kinase, interacts with calmodulin (CaM) to regulate apoptotic and autophagic signaling. Autophosphorylation of DAPK1 at Ser308 located at the autoregulatory domain (ARD) blocks CaM binding and inhibits kinase catalytic activity. However, the mechanism underlying the influence of Ser308 phosphorylation (pS308) on the DAPK1 activity remains unclear. Here, we performed multiple, microsecond length molecular dynamics (MD) simulations, the molecular mechanics generalized Born/surface area (MM-GBSA) binding free energy calculations, principal component analysis, and dynamic cross-correlation analysis to unravel the conformational dynamics and allostery of the DAPK1 - CaM interaction triggered by the pS308 at the ARD. MD simulations showed that pS308 affected the conformational stability of the DAPK1 - CaM complex. Further energetic and structural exploration revealed that pS308 weakened the association of the phosphorylated DAPK1 to CaM, which lowered the susceptibility of DAPK1 to be activated by CaM. This result can provide mechanistic insights into the molecular underpinning through which the DAPK1 kinase activity is modulated by the auto-phosphorylation.Communicated by Ramaswamy H. Sarma.
摘要：
蛋白质磷酸化在信号转导中起着重要作用，能够调节细胞活性。死亡相关蛋白激酶1(DAPK1),作为Ser/Thr激酶，与钙调蛋白（CaM）相互作用以调节凋亡和自噬信号。DAPK1在位于自动调节结构域(ARD)的Ser308处的自磷酸化阻断CaM结合并抑制激酶催化活性。然而,Ser308磷酸化(pS308)对DAPK1活性影响的潜在机制尚不清楚.这里,我们表演了多个，微秒长度分子动力学（MD）模拟，分子力学广义Born/表面积(MM-GBSA)结合自由能计算，主成分分析，和动态互相关分析，以解开由pS308在ARD触发的DAPK1-CaM相互作用的构象动力学和变构。MD模拟显示pS308影响DAPK1-CaM复合物的构象稳定性。进一步的能量和结构探索表明，pS308削弱了磷酸化的DAPK1与CaM的缔合，降低了DAPK1被CaM激活的敏感性。该结果可以提供对分子基础的机械见解，通过该分子基础，DAPK1激酶活性受到自磷酸化的调节。由RamaswamyH.Sarma沟通。
