title: Manipulation of pro-inflammatory cytokine production by the bacterial cell-penetrating effector protein YopM is independent of its interaction with host cell kinases RSK1 and PRK2.
abstract: The effector protein Yersinia outer protein M (YopM) of Yersinia enterocolitica has previously been identified and characterized as the first bacterial cell-penetrating protein (CPP). We found that recombinant YopM (rYopM) enters different eukaryotic cell types and downregulates the expression of several pro-inflammatory cytokines (e.g., tumor necrosis factor-α [TNF-α]) after autonomous translocation. After infection with Y. enterocolitica or transfection of host cells, YopM interacts with isoforms of the two kinases ribosomal S6 protein kinase (RSK) and protein kinase C-related kinase (PRK). This interaction caused sustained RSK activation due to interference with dephosphorylation. Here we demonstrate by co-immunoprecipitation that rYopM interacts with RSK and PRK following cell-penetration. We show that autonomously translocated rYopM forms a trimeric complex with different RSK and PRK isoforms. Furthermore, we constructed a series of truncated versions of rYopM to map the domain required for the formation of the complex. The C-terminus of rYopM was identified to be essential for the interaction with RSK1, whereas any deletion in rYopM's leucin-rich repeat domains abrogated PRK2 binding. Moreover, we found that the interaction of cell-penetrating rYopM with RSK led to enhanced autophosphorylation of this kinase at serine 380. Finally, we investigated whether downstream signaling of the trimeric rYopM-RSK/PRK complex modulates the expression of pro-inflammatory TNF-α. Here, we could exclude that interaction with RSK1 and PRK2 is essential for the anti-inflammatory effects of rYopM.
authors.affiliation: a Institute of Infectiology; Center for Molecular Biology of Inflammation (ZMBE); University of Münster; Münster, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Höfling
authors.forename: Julia
authors.initials: J
authors.lastname: Scharnert
authors.forename: Christoph
authors.initials: C
authors.lastname: Cromme
authors.forename: Jessica
authors.initials: J
authors.lastname: Bertrand
authors.forename: Thomas
authors.initials: T
authors.lastname: Pap
authors.forename: M Alexander
authors.initials: MA
authors.lastname: Schmidt
authors.forename: Christian
authors.initials: C
authors.lastname: Rüter
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D047468:Immunoprecipitation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011493:Protein Kinase C / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism*; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics; D015008:Yersinia enterocolitica / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C060772:yopM protein, Yersinia; C061570:protein kinase N; C069329:RPS6KA1 protein, human; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D011493:Protein Kinase C
keywords: Yersinia outer protein; YopM; anti-inflammatory; bacterial cell-penetrating proteins; pro-inflammatory cytokines; protein kinases