Pex19 is involved in importing dually targeted tail‐anchored proteins to both mitochondria and peroxisomes. (14th August 2018)

• Record Type: Journal Article
• Authors: Cichocki, Bogdan A.; Krumpe, Katrin; Vitali, Daniela G.; Rapaport, Doron
• Is Part Of: Traffic. Volume 19:Number 10(2018)
• Page Start: 770
• Page End: 785
• Publication Date: 2018-08-14
• Subjects: integral membrane protein -- mitochondria -- mitochondrial biogenesis -- outer mitochondrial membrane -- peroxisomes; Biological transport -- Periodicals; 571.6
• DOI: 10.1111/tra.12604
• Languages: English
• ISSNs: 1398-9219

Abstract

Abstract : Tail‐anchored (TA) proteins are embedded into their corresponding membrane via a single transmembrane segment at their C‐terminus whereas the majority of the protein is facing the cytosol. So far, cellular factors that mediate the integration of such proteins into the mitochondrial outer membrane were not found. Using budding yeast as a model system, we identified the cytosolic Hsp70 chaperone Ssa1 and the peroxisome import factor Pex19 as import mediators for a subset of mitochondrial TA proteins. Accordingly, deletion of PEX19 results in: (1) growth defect under respiration conditions, (2) alteration in mitochondrial morphology, (3) reduced steady‐state levels of the mitochondrial TA proteins Fis1 and Gem1, and (4) hampered in organello import of the TA proteins Fis1 and Gem1. Furthermore, recombinant Pex19 can bind directly the TA proteins Fis1 and Gem1. Collectively, this work identified the first factors that are involved in the biogenesis of mitochondrial TA proteins and uncovered an unexpected function of Pex19. Abstract : Cellular factors that mediate the integration of tail‐anchored proteins into the mitochondrial outer membrane (MOM) are unknown. We identified the peroxisome import factor Pex19 as a mediator of the biogenesis of mitochondrial TA proteins. Deletion of PEX19 results in: (i) growth defect; (ii) altered mitochondrial morphology; (iii) reduced levels of mitochondrial TA proteins; and (iv) hampered in organello import of TA proteins. Moreover, Pex19 interacted directly with mitochondrial TA proteins. Collectively, we uncovered an unexpected function of Pex19.