title: Alpha2B-adrenergic receptor interaction with tubulin controls its transport from the endoplasmic reticulum to the cell surface.
abstract: It is well recognized that the C terminus (CT) plays a crucial role in modulating G protein-coupled receptor (GPCR) transport from the endoplasmic reticulum (ER) to the cell surface. However the molecular mechanisms that govern CT-dependent ER export remain elusive. To address this issue, we used α(2B)-adrenergic receptor (α(2B)-AR) as a model GPCR to search for proteins interacting with the CT. By using peptide-conjugated affinity matrix combined with proteomics and glutathione S-transferase fusion protein pull-down assays, we identified tubulin directly interacting with the α(2B)-AR CT. The interaction domains were mapped to the acidic CT of tubulin and the basic Arg residues in the α(2B)-AR CT, particularly Arg-437, Arg-441, and Arg-446. More importantly, mutation of these Arg residues to disrupt tubulin interaction markedly inhibited α(2B)-AR transport to the cell surface and strongly arrested the receptor in the ER. These data provide the first evidence indicating that the α(2B)-AR C-terminal Arg cluster mediates its association with tubulin to coordinate its ER-to-cell surface traffic and suggest a novel mechanism of GPCR export through physical contact with microtubules.
authors.affiliation: From the Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Duvernay
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Chunmin
authors.initials: C
authors.lastname: Dong
authors.forename: Jesse J
authors.initials: JJ
authors.lastname: Guidry
authors.forename: Dan L
authors.initials: DL
authors.lastname: Sackett
authors.forename: Guangyu
authors.initials: G
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051381:Rats; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014404:Tubulin / Q000737:chemistry*
chemical_list: D018341:Receptors, Adrenergic, alpha-2; D043562:Receptors, G-Protein-Coupled; D014404:Tubulin; D005982:Glutathione Transferase