title: Molecular regulation of lysophosphatidic acid receptor 1 trafficking to the cell surface.
abstract: The lysophosphatidic acid receptor 1 (LPA1), a G-protein coupled receptor, regulates cell proliferation, migration, and cytokine release. Here, we investigate the molecular signature of LPA1 trafficking to the cell surface. The overexpressed LPA1 with a C-terminal V5 tag (LPA1-V5) is majorly expressed on the cell surface, while two deletion mutants (C320 and ∆84-87) failed to be trafficked to the cell surface. Further, site-directed mutagenesis analysis of the LPA1 revealed that Ile325, Tyr85, and Leu87 within these two fragments regulate LPA1 maturation and trafficking to the cell surface. Over-expression of Sar1, a component of coat protein complex II (COPII), enhances glycosylation of LPA1 wild type, but not these mutants. The mutants of LPA1 are majorly localized in the endoplasmic reticulum (ER) and exhibit a higher binding affinity to heat shock protein 70 (Hsp70), when compared to the LPA1 wild type. Further, we found that all these mutants failed to increase phosphorylation of Erk, and the cytokine release in response to LPA treatment. These results suggest that Ile325, Tyr85, and Leu87 within LPA1 are essential for LPA1 protein properly folding in the ER.
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Wei
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Bowser
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States; Department of Anesthesia, First Hospital of Jilin University, Changchun, China.
authors.forename: Su
authors.initials: S
authors.lastname: Dong
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Shuqi
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States. Electronic address: zhaoy3@upmc.edu.
authors.forename: Yutong
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000818:Animals; D022181:COP-Coated Vesicles / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D017510:Protein Folding; D021381:Protein Transport / Q000502:physiology; D049368:Receptors, Lysophosphatidic Acid / Q000235:genetics / Q000378:metabolism*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D049368:Receptors, Lysophosphatidic Acid; D048049:Extracellular Signal-Regulated MAP Kinases; D020559:Monomeric GTP-Binding Proteins
keywords: Cell surface trafficking; ER quality control; GPCR; Mutation