Cytokine‐dependent activation of JAK‐STAT pathway in Saccharomyces cerevisiae. Issue 8 (2nd March 2016)

• Record Type: Journal Article
• Authors: Yoshimoto, Nobuo; Ikeda, Yuko; Tatematsu, Kenji; Iijima, Masumi; Nakai, Tadashi; Okajima, Toshihide; Tanizawa, Katsuyuki; Kuroda, Shun'ichi
• Is Part Of: Biotechnology and bioengineering. Volume 113:Issue 8(2016)
• Page Start: 1796
• Page End: 1804
• Publication Date: 2016-03-02
• Subjects: yeast -- cell surface display -- JAK‐STAT pathway -- phosphotyrosine -- tyrosine kinase; Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.25948
• Languages: English
• ISSNs: 0006-3592

Abstract

ABSTRACT: Protein phosphorylation is an important post‐translational modification for intracellular signaling molecules, mostly found in serine and threonine residues. Tyrosine phosphorylations are very few events (less than 0.1% to phosphorylated serine/threonine residues), but capable of governing cell fate decisions involved in proliferation, differentiation, apoptosis, and oncogenic transformation. Hence, it is important for drug discovery and system biology to measure the intracellular level of phosphotyrosine. Although mammalian cells have been conventionally utilized for this purpose, accurate determination of phosphotyrosine level often suffers from high background due to the unexpected crosstalk among endogenous signaling molecules. This situation led us firstly to establish the ligand‐induced activation of homomeric receptor tyrosine kinase (i.e., epidermal growth factor receptor) in Saccharomyces cerevisiae, a lower eukaryote possessing organelles similar to higher eukaryote but not showing substantial level of tyrosine kinase activity. In this study, we expressed heteromeric receptor tyrosine kinase (i.e., a complex of interleukin‐5 receptor (IL5R) α chain, common β chain, and JAK2 tyrosine kinase) in yeast. When coexpressed with a cell wall‐anchored form of IL5, the yeast exerted the autophosphorylation of JAK2, followed by the phosphorylation of transcription factor STAT5a and subsequent nuclear accumulation of phosphorylated STAT5a. Taken together, yeast could be an ideal host for sensitive detection of phosphotyrosine generated by a wide variety of tyrosine kinases. Biotechnol. Bioeng. 2016;113: 1796–1804. © 2016 Wiley Periodicals, Inc. Abstract : Yoshimoto and coworkers succeeded in the reconstitution of signaling complex consisting of interleukin 5 receptor (IL5R) α chain, common β chain (βc), and JAK2 in the plasma membrane of yeast cells. The cell wall‐anchored form of IL5 could execute the autophosphorylation of JAK2, followed by tyrosine phosphorylation of STAT5a and subsequent nuclear translocation of phosphorylated STAT5a.