作物学报2026，Vol.52Issue(9)：2608-2617,10.DOI:10.3724/SP.J.1006.2026.64003
木薯MeGRXC3 通过其关键功能位点介导对MeCAT1 酶活性的特异性调控
Cassava MeGRXC3 mediates specific regulation of MeCAT1 enzyme activity via its key functional sites
摘要
Abstract
Glutaredoxins play a critical role in plant stress responses by modulating the redox state of cysteine residues in target proteins.Previous studies have shown that the cassava CC-type glutaredoxin MeGRXC3 interacts with catalase MeCAT1 and negatively regulates its enzyme activity,yet the underlying molecular mechanism remains unclear.To elucidate the regulatory effects of key functional sites of MeGRXC3 on MeCAT1 enzyme activity,this study constructed expression vectors carrying mu-tations in active domain(C21AC24A)and glutathione-binding domain(G75L)of MeGRXC3.Subcellular localization analysis indicated that mutations in these functional domains did not alter the intracellular localization of MeGRXC3.Yeast two-hybrid,bimolecular fluorescence complementation,and pull-down assays confirmed that MeGRXC3 interacts with MeCAT1 both in vivo and in vitro,and this interaction is independent of the aforementioned functional domains.However,transient expression in to-bacco and biochemical analysis revealed that the negative regulation of MeCAT1 enzyme activity by MeGRXC3 is closely related to these two functional domains:mutation of the active domain attenuated the inhibitory effect,while mutation of the glu-tathione-binding domain completely abolished the inhibition,leading to a significant enhancement of MeCAT1 enzyme activity.These results demonstrate that the catalytic active domain and the predicted glutathione-binding domain of MeGRXC3,while dispensable for its physical interaction with MeCAT1,are essential for inhibiting MeCAT1 enzymatic activity.This indicates that MeGRXC3 likely binds to MeCAT1 through other regions/domains,subsequently depending on its conserved functional sites to execute its inhibitory role.This finding provides a crucial foundation for further elucidating the precise molecular mechanism by which MeGRXC3 regulates MeCAT1 activity at the post-translational level.关键词
木薯/MeGRXC3/活性位点/谷胱甘肽结合位点/MeCAT1/过氧化氢酶活性Key words
cassava/MeGRXC3/active site/glutathione-binding site/MeCAT1/catalase activity引用本文复制引用
王瑞霞,于晓玲,李淑霞,张秀春,郭鑫,甘萍,阮孟斌..木薯MeGRXC3 通过其关键功能位点介导对MeCAT1 酶活性的特异性调控[J].作物学报,2026,52(9):2608-2617,10.基金项目
本研究由国家自然科学基金项目(32360458,32272037)资助.This study was supported by the National Natural Science Foundation of China(32360458,32272037). （32360458,32272037）
