title: The bud tip is the cellular hot spot of protein secretion in yeasts.
abstract: Yeasts are valuable hosts for recombinant protein production. Among them, Pichia pastoris is frequently used for production of secreted proteins, and much effort was made to improve the secretion efficiency of this expression platform. However, the knowledge on the secretion machinery is mainly based on studies in Saccharomyces cerevisiae. Therefore, it is of great interest for targeted improvement of the system to learn more about the secretion process in P. pastoris. Using human serum albumin, a protein which is produced in high quantities in P. pastoris, we show here the secretion pathway of this protein. During passage of the secretory route, the recombinant protein is mainly localized in the endoplasmic reticulum (ER) and in COPII vesicles, and is inherited to the daughter cell via the perinuclear ER. The final release to the cell exterior occurs at the bud, initiating at the bud tip and later spreading over the entire bud surface. The same polarized secretion pattern was observed for a recombinant antibody light chain and the native secretory protein Epx1 of P. pastoris. Clarifying the point of release of secretory proteins will have major impact on engineering the secretory pathway of P. pastoris and other budding yeasts.
authors.affiliation: Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.|Austrian Centre of Industrial Biotechnology (ACIB GmbH), Vienna, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Puxbaum
authors.affiliation: Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.|Austrian Centre of Industrial Biotechnology (ACIB GmbH), Vienna, Austria.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gasser
authors.affiliation: Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria. diethard.mattanovich@boku.ac.at.|Austrian Centre of Industrial Biotechnology (ACIB GmbH), Vienna, Austria. diethard.mattanovich@boku.ac.at.
authors.forename: Diethard
authors.initials: D
authors.lastname: Mattanovich
mesh_terms: D000418:Albumins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000378:metabolism; D010843:Pichia / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism*; D004718:Saccharomycetales / Q000378:metabolism*
chemical_list: D000418:Albumins; D005656:Fungal Proteins; D007147:Immunoglobulin Light Chains; D011994:Recombinant Proteins
keywords: Bud; Fluorescence microscopy; Pichia pastoris; Protein secretion; Recombinant protein; Subcellular localization