Human ASPL-TUG interacts with p97 and complements the proteasome mislocalization of a yeast ubx4 mutant, but not the ER-associated degradation defectReport as inadecuate




Human ASPL-TUG interacts with p97 and complements the proteasome mislocalization of a yeast ubx4 mutant, but not the ER-associated degradation defect - Download this document for free, or read online. Document in PDF available to download.

BMC Cell Biology

, 15:31

Protein degradation and cell death

Abstract

BackgroundIn mammalian cells, ASPL is involved in insulin-stimulated redistribution of the glucose transporter GLUT4 and assembly of the Golgi apparatus. Its putative yeast orthologue, Ubx4, is important for proteasome localization, endoplasmic reticulum-associated protein degradation ERAD, and UV-induced degradation of RNA polymerase.

ResultsHere, we show that ASPL is a cofactor of the hexameric ATPase complex, known as p97 or VCP in mammals and Cdc48 in yeast. In addition, ASPL interacts in vitro with NSF, another hexameric ATPase complex. ASPL localizes to the ER membrane. The central area in ASPL, containing both a SHP box and a UBX domain, is required for binding to the p97 N-domain. Knock-down of ASPL does not impair degradation of misfolded secretory proteins via the ERAD pathway. Deletion of UBX4 in yeast causes cycloheximide sensitivity, while ubx4 cdc48-3 double mutations cause proteasome mislocalization. ASPL alleviates these defects, but not the impaired ERAD.

ConclusionsIn conclusion, ASPL and Ubx4 are homologous proteins with only partially overlapping functions. Both interact with p97-Cdc48, but while Ubx4 is important for ERAD, ASPL appears not to share this function.

KeywordsUbiquitin Proteasome Chaperone Degradation AbbreviationsASPLAlveolar soft part sarcoma locus

CBBCoomassie brilliant blue

CHXCycloheximide

EREndoplasmic reticulum

ERADER-associated degradation

GSHGlutathione

IPImmunoprecipitation

LHULow homology UBX

NEMN-ethylmaleimide

NSFNEM sensitive factor

TUGTether containing UBX domain of GLUT4

VCPValosin-containing protein

3AT3-aminotriazol.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2121-15-31 contains supplementary material, which is available to authorized users.

Louise Madsen, Karen Molbæk contributed equally to this work.

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Author: Louise Madsen - Karen Molbæk - Ida B Larsen - Sofie V Nielsen - Esben G Poulsen - Peter S Walmod - Kay Hofmann - Micha

Source: https://link.springer.com/



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