Abstract

Identifying isoform-specific inhibitors for closely related kinase family members remains a substantial challenge. The necessity for achieving this specificity is exemplified by the RSK family, downstream effectors of ERK1/2, which have divergent physiological effects. The natural product, SL0101, a flavonoid glycoside, binds specifically to RSK1/2 through a binding pocket generated by an extensive conformational rearrangement within the RSK N-terminal kinase domain (NTKD). In modelling experiments a single amino acid that is divergent in RSK3/4 most likely prevents the required conformational rearrangement necessary for SL0101 binding. Kinetic analysis of RSK2 association with SL0101 and its derivatives identified that regions outside of the NTKD contribute to stable inhibitor binding. An analogue with an n-propyl-carbamate at the 4” position on the rhamnose moiety was identified that forms a highly stable inhibitor complex with RSK2 but not with RSK1. These results identify a SL0101 modification that will aid the identification of RSK2 specific inhibitors.

摘要

鉴定密切相关的激酶家族成员的异构体特异性抑制剂仍然是一个巨大的挑战。实现这种特异性的必要性以 RSK 家族为例，它是 ERK1/2 的下游效应器，具有不同的生理效应。天然产物 SL0101 是一种类黄酮糖苷，通过 RSK N 末端激酶结构域 (NTKD) 内的广泛构象重排产生的结合口袋与 RSK1/2 特异性结合。在建模实验中，在 RSK3/4 中不同的单个氨基酸最有可能阻止 SL0101 结合所需的构象重排。RSK2 与 SL0101 及其衍生物关联的动力学分析确定 NTKD 之外的区域有助于稳定的抑制剂结合。具有n的类似物鼠李糖部分 4" 位置的氨基甲酸丙酯与 RSK2 形成高度稳定的抑制剂复合物，但不与 RSK1 形成高度稳定的抑制剂复合物。这些结果确定了 SL0101 修饰，这将有助于识别 RSK2 特异性抑制剂。