eprintid: 19249 rev_number: 20 userid: 1419 dir: disk0/00/01/92/49 datestamp: 2013-07-03 15:46:02 lastmod: 2019-02-02 15:57:07 status_changed: 2013-07-03 15:46:02 type: article metadata_visibility: show item_issues_count: 0 eprint_status: archive creators_name: Rabu, C creators_name: Wipf, P creators_name: Brodsky, JL creators_name: High, S creators_email: creators_email: pwipf@pitt.edu creators_email: jbrodsky@pitt.edu creators_email: creators_id: creators_id: PWIPF creators_id: JBRODSKY creators_id: creators_orcid: creators_orcid: creators_orcid: 0000-0002-6984-8486 creators_orcid: title: A precursor-specific role for Hsp40/Hsc70 during tail-anchored protein integration at the endoplasmic reticulum ispublished: pub divisions: sch_as_chemistry full_text_status: public abstract: Tail-anchored (TA) protein synthesis at the endoplasmic reticulum (ER) represents a distinct and novel process that provides a paradigm for understanding post-translational membrane insertion in eukaryotes. The major route for delivering TA proteins to the ER requires both ATP and one or more cytosolic factors that facilitate efficient membrane insertion. Until recently, the identity of these cytosolic components was elusive, but two candidates have now been suggested to promote ATP-dependent TA protein integration. The first is the cytosolic chaperone complex of Hsp40/Hsc70, and the second is a novel ATPase denoted Asna-1 or TRC40. In this study we focus on the role of the Hsp40/Hsc70 complex in promoting TA protein biogenesis at the ER. We show that the membrane integration of most TA proteins is stimulated by Hsp40/Hsc70 when using purified components and a reconstituted system. In contrast, when both Hsp40/Hsc70 and Asna-1/TRC40 are provided as a complete system, small molecule inhibition of Hsp40/Hsc70 indicates that only a subset of TA proteins are obligatory clients for this chaperone-mediated delivery route. We show that the hydrophobicity of the TA region dictates whether a precursor is delivered to the ER via the Hsp40/Hsc70 or Asna-1/TRC40-dependent route, and we conclude that these distinct cytosolic ATPases are responsible for two different ATP-dependent pathways of TA protein biogenesis. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc. date: 2008-10-10 date_type: published publication: Journal of Biological Chemistry volume: 283 number: 41 pagerange: 27504 - 27513 refereed: TRUE issn: 0021-9258 id_number: 10.1074/jbc.M804591200 other_id: NLM PMC2562055 pmcid: PMC2562055 pmid: 18667436 mesh_headings: Adenosine Triphosphate--metabolism mesh_headings: Animals mesh_headings: Arsenite Transporting ATPases--metabolism mesh_headings: Endoplasmic Reticulum--metabolism mesh_headings: HSC70 Heat-Shock Proteins--metabolism mesh_headings: HSP40 Heat-Shock Proteins--metabolism mesh_headings: HeLa Cells mesh_headings: Humans mesh_headings: Hydrophobic and Hydrophilic Interactions mesh_headings: Intracellular Membranes--metabolism mesh_headings: Membrane Proteins--metabolism mesh_headings: Mice mesh_headings: Multiprotein Complexes--metabolism mesh_headings: Protein Structure, Tertiary--physiology mesh_headings: Protein Transport--physiology mesh_headings: Rats chemical_names: ASNA1 protein, human chemical_names: DNAJB1 protein, human chemical_names: HSC70 Heat-Shock Proteins chemical_names: HSP40 Heat-Shock Proteins chemical_names: HSPA8 protein, human chemical_names: Membrane Proteins chemical_names: Multiprotein Complexes chemical_names: Adenosine Triphosphate chemical_names: Arsenite Transporting ATPases citation: Rabu, C and Wipf, P and Brodsky, JL and High, S (2008) A precursor-specific role for Hsp40/Hsc70 during tail-anchored protein integration at the endoplasmic reticulum. Journal of Biological Chemistry, 283 (41). 27504 - 27513. ISSN 0021-9258 document_url: http://d-scholarship-dev.library.pitt.edu/19249/1/licence.txt