crystal structures of the tetratricopeptide repeat domains of kinesin light chains insight into cargo recognition mechanisms晶体结构的tetratricopeptide重复域驱动蛋白轻链洞察货物识别机制.pdf

Crystal Structures of the Tetratricopeptide Repeat Domains of Kinesin Light Chains: Insight into Cargo Recognition Mechanisms 1. 2. 1 1 2 1 Haizhong Zhu , Han Youl Lee , Yufeng Tong , Bum-Soo Hong , Kyung-Phil Kim , Yang Shen , Kyung 3 1 1 1,2 Jik Lim , Farrell Mackenzie , Wolfram Tempel , Hee-Won Park * 1 Structural Genomics Consortium, Toronto, Ontario, Canada, 2 Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada, 3 Philip Pocock Catholic Secondary School, Mississauga, Ontario, Canada Abstract Kinesin-1 transports various cargos along the axon by interacting with the cargos through its light chain subunit. Kinesin light chains (KLC) utilize its tetratricopeptide repeat (TPR) domain to interact with over 10 different cargos. Despite a high sequence identity between their TPR domains (87%), KLC1 and KLC2 isoforms exhibit differential binding properties towards some cargos. We determined the structures of human KLC1 and KLC2 tetratricopeptide repeat (TPR) domains using X-ray crystallography and investigated the different mechanisms by which KLCs interact with their cargos. Using isothermal titration calorimetry, we attributed the specific interaction between KLC1 and JNK-interacting protein 1 (JIP1) cargo to residue N343 in the fourth TRP repeat. Structurally, the N343 residue is adjacent to other asparagines and lysines, creating a positively charged polar patch within the groove of the TPR domain. Whereas, KLC2 with the corresponding residue S