The ER membrane protein complex (EMC) is required for the biogenesis of a subset of tail anchored (TA) and polytopic membrane proteins, including Rhodopsin-1 (Rh1) and the TRP channel. To understand the physiological implications of EMC-dependent membrane protein biogenesis, we perform a bioinformatic identification of Drosophila TA proteins. From 254 predicted TA proteins, screening in larval eye discs identified two proteins that require EMC for their biogenesis: fan and Xport-A. Fan is required for male fertility in Drosophila and we show that EMC is also required for this process. Xport-A is essential for the biogenesis of both Rh1 and TRP, raising the possibility that disruption of Rh1 and TRP biogenesis in EMC mutants is secondary to the Xport-A defect. We show that EMC is required for Xport-A TMD membrane insertion and that EMC-independent Xport-A mutants rescue Rh1 and TRP biogenesis in EMC mutants. Finally, our work also reveals a role for Xport-A in a glycosylation-dependent triage mechanism during Rh1 biogenesis in the endoplasmic reticulum.

• Klíčová slova
• ER membrane protein complex, Rh1, TRP, Xport-A, tail anchored proteins,
• MeSH
• Drosophila genetika   metabolismus   MeSH
• endoplazmatické retikulum metabolismus   MeSH
• membránové proteiny genetika   metabolismus   MeSH
• molekulární chaperony * genetika   metabolismus   MeSH
• proteiny Drosophily * genetika   metabolismus   MeSH
• represorové proteiny * genetika   metabolismus   MeSH
• rodopsin * genetika   MeSH
• transkripční faktory bHLH * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• emc protein, Drosophila MeSH Prohlížeč
• membránové proteiny MeSH
• molekulární chaperony * MeSH
• proteiny Drosophily * MeSH
• represorové proteiny * MeSH
• rodopsin * MeSH
• transkripční faktory bHLH * MeSH
• Xport-A protein, Drosophila MeSH Prohlížeč

The apical inflammatory cytokine TNF regulates numerous important biological processes including inflammation and cell death, and drives inflammatory diseases. TNF secretion requires TACE (also called ADAM17), which cleaves TNF from its transmembrane tether. The trafficking of TACE to the cell surface, and stimulation of its proteolytic activity, depends on membrane proteins, called iRhoms. To delineate how the TNF/TACE/iRhom axis is regulated, we performed an immunoprecipitation/mass spectrometry screen to identify iRhom-binding proteins. This identified a novel protein, that we name iTAP (iRhom Tail-Associated Protein) that binds to iRhoms, enhancing the cell surface stability of iRhoms and TACE, preventing their degradation in lysosomes. Depleting iTAP in primary human macrophages profoundly impaired TNF production and tissues from iTAP KO mice exhibit a pronounced depletion in active TACE levels. Our work identifies iTAP as a physiological regulator of TNF signalling and a novel target for the control of inflammation.

• Klíčová slova
• TACE/ADAM17, Tumour Necrosis Factor (TNF), biochemistry, cell biology, chemical biology, human, iRhom2, inflammation, lysosome, mouse, vesicular trafficking, FRMD8,
• MeSH
• buněčné linie MeSH
• cytoskeletální proteiny genetika   metabolismus   MeSH
• endozomy metabolismus   MeSH
• fibroblasty cytologie   metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• intracelulární signální peptidy a proteiny MeSH
• lidé MeSH
• makrofágy cytologie   metabolismus   MeSH
• membránové proteiny genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• primární buněčná kultura MeSH
• protein ADAM17 genetika   metabolismus   MeSH
• proteolýza MeSH
• RAW 264.7 buňky MeSH
• regulace genové exprese MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• sekvenční seřazení MeSH
• signální transdukce MeSH
• TNF-alfa genetika   metabolismus   MeSH
• transportní proteiny genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ADAM17 protein, human MeSH Prohlížeč
• cytoskeletální proteiny MeSH
• intracelulární signální peptidy a proteiny MeSH
• membránové proteiny MeSH
• protein ADAM17 MeSH
• RHBDF2 protein, human MeSH Prohlížeč
• TNF-alfa MeSH
• transportní proteiny MeSH