title: 14-3-3 protein interacts with Huntingtin-associated protein 1 and regulates its trafficking.
abstract: HAP1 (Huntingtin-associated protein 1) consists of two alternately spliced isoforms (HAP1A and HAP1B, which have unique C-terminal sequences) and participates in intracellular trafficking. The C terminus of HAP1A is phosphorylated, and this phosphorylation was found to decrease the association of HAP1A with kinesin light chain, a protein involved in anterograde transport in cells. It remains unclear how this phosphorylation functions to regulate the association of HAP1 with trafficking proteins. Using the yeast two-hybrid system, we found that HAP1 also interacts with 14-3-3 proteins, which are involved in the assembly of protein complexes and the regulation of protein trafficking. The interaction of HAP1 with 14-3-3 is confirmed by their immunoprecipitation and colocalization in mouse brain. Moreover, this interaction is specific to HAP1A and is increased by the phosphorylation of the C terminus of HAP1A. We also found that expression of 14-3-3 decreases the association of HAP1A with kinesin light chain. As a result, there is less HAP1A distributed in neurite tips of PC12 cells that overexpress 14-3-3. Also, overexpression of 14-3-3 reduces the effect of HAP1A in promoting neurite outgrowth of PC12 cells. We propose that the phosphorylation-dependent interaction of HAP1A with 14-3-3 regulates HAP1 function by influencing its association with kinesin light chain and trafficking in neuronal processes.
authors.affiliation: Department of Human Genetics and the Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Juan
authors.initials: J
authors.lastname: Rong
authors.affiliation: Department of Human Genetics and the Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Shihua
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Human Genetics and the Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Sheng
authors.affiliation: Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: Meng
authors.initials: M
authors.lastname: Wu
authors.affiliation: Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: Brian
authors.initials: B
authors.lastname: Coblitz
authors.affiliation: Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322 and the.
authors.forename: Haian
authors.initials: H
authors.lastname: Fu
authors.affiliation: Department of Human Genetics and the Emory University School of Medicine, Atlanta, Georgia 30322. Electronic address: xiaoli@genetics.emory.edu.
authors.forename: Xiao-Jiang
authors.initials: XJ
authors.lastname: Li
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing / Q000502:physiology; D000818:Animals; D001921:Brain / Q000378:metabolism; D015870:Gene Expression; D016547:Kinesins; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D020798:Two-Hybrid System Techniques
chemical_list: D048948:14-3-3 Proteins; C490758:Hap1 protein, mouse; C490757:Hap1 protein, rat; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D016547:Kinesins