title: Zinc binding site in PICK1 is dominantly located at the CPC motif of its PDZ domain.
abstract: PICK1 (protein interacting with Ckinase 1) containing a PDZ domain, a BAR domain, and two short acidic regions is as an adaptor protein that plays an important role in alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor trafficking, cell morphology and migration, as well as in some diseases such as cancer, schizophrenia and pain. To better understand the physiological function of PICK1, we expressed the recombinant PICK1 and its truncated mutants in E.coli, and measured their zinc binding properties by fluorescence and competition assay. It is shown that PICK1 has one Zn2+-binding site. The Zn2+-binding properties of PICK1 are not appreciably affected after the removal of BARC domain (involving BAR domain and C-terminal acidic region). Deleting the N-terminal acidic region of NPDZ domain (involving PDZ domain and N-terminal acidic region) in PICK1 impairs its Zn2+-binding capacity. The mutation of the CPC (Cys-Pro-Cys) motif in the PDZ domain of PICK1 abolishes the ability of Zn2+-binding. In addition, Zn2+ can enhance the lipid-binding ability of PDZ domain as observed in both protein-lipid overlay assay and fluorescence analysis. The results presented in this report suggested that Zn2+ plays a regulatory role in the trafficking of PICK1 from the cytoplasm to cell membrane.
authors.affiliation: Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Shanxi University, Taiyuan, China. yaweishi@sxu.edu.cn
authors.forename: Yawei
authors.initials: Y
authors.lastname: Shi
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Jingming
authors.initials: J
authors.lastname: Yuan
authors.forename: Hong
authors.initials: H
authors.lastname: Xiao
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Yang
authors.forename: Lixi
authors.initials: L
authors.lastname: Niu
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002417:Cattle; D003598:Cytoskeletal Proteins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D054731:PDZ Domains / Q000502:physiology*; D011485:Protein Binding / Q000502:physiology; D051381:Rats; D015032:Zinc / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D009687:Nuclear Proteins; C498298:PICK1 protein, rat; D015032:Zinc