Structural and biochemical insights into the homotypic PB1-PB1 complex between PKCζ and p62  

作　　者：REN Jun WANG Jue WANG ZhiXin WU JiaWei 

机构地区：[1]MOE Key Laboratory of Protein Science and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University

出　　处：《Science China(Life Sciences)》2014年第1期69-80,共12页中国科学（生命科学英文版）

基　　金：supported in part by the National Natural Science Foundation of China(31070643 and 31130062);Tsinghua University(20121080028)

摘　　要：The atypical PKC isoforms （ζ and t） play essential roles in regulating various cellular processes. Both the hetero-interaction between PKCζand p62 through their N-terminal PB 1 domains and the homo-oligomerization of p62 via its PB 1 domain are critical for the activation of NF-r.B signaling; however, the molecular mechanisms concerning the formation and regulation of these homotypic complexes remain unclear. Here we determined the crystal structure of PKCζ-PB 1 in complex with a mono- meric p62-PB 1 mutant, where the massive electrostatic interactions between the acidic OPCA motif of PKCζ-PB 1 and the basic surface of p62-PB 1, as well as additional hydrogen bonds, ensure the formation of a stable and specific complex. The PKCζ-p62 interaction is interfered with the modification of a specific Cys of PKCζ by the antiarthritis drug aurothiomalate, though all four cysteine residues in the PKCζ-PB 1 domain can be modified in in vitro assay. In addition, detailed structural and biochemical analyses demonstrate that the PB 1 domains of aPKCs belong to the type I group, which can depolymerize the high-molecular-weight p62 aggregates into homo-oligomers of lower order. These data together unravel the molecular mecha- nisms of the homo- or hetero-interactions between p62 and PKCζ and provide the basis for designing inhibitors of NF-r,.B sig- naling.The atypical PKC isoforms(ζandι)play essential roles in regulating various cellular processes.Both the hetero-interaction between PKCζand p62 through their N-terminal PB1 domains and the homo-oligomerization of p62 via its PB1 domain are critical for the activation of NF-B signaling;however,the molecular mechanisms concerning the formation and regulation of these homotypic complexes remain unclear.Here we determined the crystal structure of PKCζ-PB1 in complex with a monomeric p62-PB1 mutant,where the massive electrostatic interactions between the acidic OPCA motif of PKCζ-PB1 and the basic surface of p62-PB1,as well as additional hydrogen bonds,ensure the formation of a stable and specific complex.The PKCζ-p62 interaction is interfered with the modification of a specific Cys of PKCζby the antiarthritis drug aurothiomalate,though all four cysteine residues in the PKCζ-PB1 domain can be modified in in vitro assay.In addition,detailed structural and biochemical analyses demonstrate that the PB1 domains of aPKCs belong to the type I group,which can depolymerize the high-molecular-weight p62 aggregates into homo-oligomers of lower order.These data together unravel the molecular mechanisms of the homo-or hetero-interactions between p62 and PKCζand provide the basis for designing inhibitors of NF-B signaling.

关 键 词：PKC P62 PB1 domain heterodimerization and homo-oligomerization aurothiomalate 

分 类 号：R341[医药卫生—基础医学]