title: The prodomain of Ssy5 protease controls receptor-activated proteolysis of transcription factor Stp1.
abstract: Extracellular amino acids induce the yeast SPS sensor to endoproteolytically cleave transcription factors Stp1 and Stp2 in a process termed receptor-activated proteolysis (RAP). Ssy5, the activating endoprotease, is synthesized with a large N-terminal prodomain and a C-terminal chymotrypsin-like catalytic (Cat) domain. During biogenesis, Ssy5 cleaves itself and the prodomain and Cat domain remain associated, forming an inactive primed protease. Here we show that the prodomain is a potent inhibitor of Cat domain activity and that its inactivation is a requisite for RAP. Accordingly, amino acid-induced signals trigger proteasome-dependent degradation of the prodomain. A mutation that stabilizes the prodomain prevents Stp1 processing, whereas destabilizing mutations lead to constitutive RAP-independent Stp1 processing. We fused a conditional degron to the prodomain to synthetically reprogram the amino acid-responsive SPS signaling pathway, placing it under temperature control. Our results define a regulatory mechanism that is novel for eukaryotic proteases functioning within cells.
authors.affiliation: Stockholm University, Wenner-Gren Institute, S-106 91 Stockholm, Sweden.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Pfirrmann
authors.forename: Stijn
authors.initials: S
authors.lastname: Heessen
authors.forename: Deike J
authors.initials: DJ
authors.lastname: Omnus
authors.forename: Claes
authors.initials: C
authors.lastname: Andréasson
authors.forename: Per O
authors.initials: PO
authors.lastname: Ljungdahl
mesh_terms: D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D057057:Serine Proteases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C074632:STP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D010450:Endopeptidases; D057057:Serine Proteases; C550846:Ssy5 protein, S cerevisiae; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease