title: 14-3-3τ promotes surface expression of Cav2.2 (α1B) Ca2+ channels.
abstract: Surface expression of voltage-gated Ca(2+) (Cav) channels is important for their function in calcium homeostasis in the physiology of excitable cells, but whether or not and how the α1 pore-forming subunits of Cav channels are trafficked to plasma membrane in the absence of the known Cav auxiliary subunits, β and α2δ, remains mysterious. Here we showed that 14-3-3 proteins promoted functional surface expression of the Cav2.2 α1B channel in transfected tsA-201 cells in the absence of any known Cav auxiliary subunit. Both the surface to total ratio of the expressed α1B protein and the current density of voltage step-evoked Ba(2+) current were markedly suppressed by the coexpression of a 14-3-3 antagonist construct, pSCM138, but not its inactive control, pSCM174, as determined by immunofluorescence assay and whole cell voltage clamp recording, respectively. By contrast, coexpression with 14-3-3τ significantly enhanced the surface expression and current density of the Cav2.2 α1B channel. Importantly, we found that between the two previously identified 14-3-3 binding regions at the α1B C terminus, only the proximal region (amino acids 1706-1940), closer to the end of the last transmembrane domain, was retained by the endoplasmic reticulum and facilitated by 14-3-3 to traffic to plasma membrane. Additionally, we showed that the 14-3-3/Cav β subunit coregulated the surface expression of Cav2.2 channels in transfected tsA-201 cells and neurons. Altogether, our findings reveal a previously unidentified regulatory function of 14-3-3 proteins in promoting the surface expression of Cav2.2 α1B channels.
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Hao
authors.initials: H
authors.lastname: Sun
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Xiuqun
authors.initials: X
authors.lastname: Zou
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Lingling
authors.initials: L
authors.lastname: Feng
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Zhaoyuan
authors.initials: Z
authors.lastname: Hou
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and.
authors.forename: Aiwu
authors.initials: A
authors.lastname: Zhou
authors.affiliation: the Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and liyong68@shsmu.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D020864:Calcium Channels, N-Type / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004594:Electrophysiology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D047468:Immunoprecipitation; D011485:Protein Binding; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D048948:14-3-3 Proteins; D020864:Calcium Channels, N-Type
keywords: 14-3-3tau; Calcium Channel; Cav 2.2 Channel; Cav Auxiliary Subunits; Electrophysiology; Endoplasmic Reticulum Retention; Membrane Trafficking; Protein-Protein Interaction; Trafficking