PDF(Pubmed)
Abstract：
SUCROSE-NON-FERMENTING1-RELATED PROTEIN KINASE1 (SnRK1), a central plant metabolic sensor kinase, phosphorylates its target proteins, triggering a global shift from anabolism to catabolism. Molecular modeling revealed that upon binding of KIN10 to GEMINIVIRUS REP-INTERACTING KINASE1 (GRIK1), KIN10\'s activation T-loop reorients into GRIK1\'s active site, enabling its phosphorylation and activation. Trehalose 6-phosphate (T6P) is a proxy for cellular sugar status and a potent inhibitor of SnRK1. T6P binds to KIN10, a SnRK1 catalytic subunit, weakening its affinity for GRIK1. Here, we investigate the molecular details of T6P inhibition of KIN10. Molecular dynamics simulations and in vitro phosphorylation assays identified and validated the T6P binding site on KIN10. Under high-sugar conditions, T6P binds to KIN10, blocking the reorientation of its activation loop and preventing its phosphorylation and activation by GRIK1. Under these conditions, SnRK1 maintains only basal activity levels, minimizing phosphorylation of its target proteins, thereby facilitating a general shift from catabolism to anabolism.
摘要：
蔗糖-非FERMENTING1相关蛋白激酶1(SnRK1),一种中心植物代谢感应激酶，磷酸化其目标蛋白，引发了从合成代谢到分解代谢的全球转变。分子模型显示，在KIN10与GeminivirusREP-INASERATINGKINASE1（GRIK1）结合后，KIN10的激活T环重新定向到GRIK1的激活位点,使其磷酸化和激活。海藻糖6-磷酸（T6P）是细胞糖状态的代理和SnRK1的有效抑制剂。T6P与SnRK1催化亚基KIN10结合，削弱其对GRIK1的亲和力。这里,我们研究了T6P抑制KIN10的分子细节。分子动力学模拟和体外磷酸化测定鉴定并验证了KIN10上的T6P结合位点。在高糖条件下,T6P与KIN10结合，阻断其激活环的重新定向，并阻止其磷酸化和被GRIK1激活。在这些条件下,SnRK1仅维持基础活动水平，最小化其靶蛋白的磷酸化，从而促进从分解代谢到合成代谢的普遍转变。
