Ligand stimulation of CD95 induces activation of Plk3 followed by phosphorylation of caspase-8.
Upon interaction of the CD95 receptor with its ligand, sequential association of the adaptor molecule FADD (MORT1), pro-forms of caspases-8/10, and the caspase-8/10 regulator c-FLIP leads to the formation of a death-inducing signaling complex. Here, we identify polo-like kinase (Plk) 3 as a new interaction partner of the death receptor CD95. The enzymatic activity of Plk3 increases following interaction of the CD95 receptor with its ligand. Knockout (KO) or knockdown of caspase-8, CD95 or FADD prevents activation of Plk3 upon CD95 stimulation, suggesting a requirement of a functional DISC for Plk3 activation. Furthermore, we identify caspase-8 as a new substrate for Plk3. Phosphorylation occurs on T273 and results in stimulation of caspase-8 proapoptotic function. Stimulation of CD95 in cells expressing a non-phosphorylatable caspase-8-T273A mutant in a rescue experiment or in Plk3-KO cells generated by CRISPR/Cas9 reduces the processing of caspase-8 prominently. Low T273 phosphorylation correlates significantly with low Plk3 expression in a cohort of 95 anal tumor patients. Our data suggest a novel mechanism of kinase activation within the Plk family and propose a new model for the stimulation of the extrinsic death pathway in tumors with high Plk3 expression.
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.
Christina
C
Helmke
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.
Monika
M
Raab
Department of Radiotherapy and Oncology, Goethe University, 60590 Frankfurt, Germany.|German Cancer Consortium (DKTK)/German Cancer Research Center, 69120 Heidelberg, Germany.
Franz
F
Rödel
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.|German Cancer Consortium (DKTK)/German Cancer Research Center, 69120 Heidelberg, Germany.
Yves
Y
Matthess
German Cancer Consortium (DKTK)/German Cancer Research Center, 69120 Heidelberg, Germany.|Department of Medicine II, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Thomas
T
Oellerich
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.|German Cancer Consortium (DKTK)/German Cancer Research Center, 69120 Heidelberg, Germany.
Ranadip
R
Mandal
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.
Mourad
M
Sanhaji
Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.|Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.
Henning
H
Urlaub
Department of Radiotherapy and Oncology, Goethe University, 60590 Frankfurt, Germany.|German Cancer Consortium (DKTK)/German Cancer Research Center, 69120 Heidelberg, Germany.
Claus
C
Rödel
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.
Sven
S
Becker
Department of Gynecology, Goethe University, 60590 Frankfurt, Germany.|German Cancer Consortium (DKTK)/German Cancer Research Center, 69120 Heidelberg, Germany.
Klaus
K
Strebhardt
D053181:Caspase 8 / Q000378:metabolism*; D053418:Death Domain Receptor Signaling Adaptor Proteins / Q000378:metabolism; D004789:Enzyme Activation; D053200:Fas-Associated Death Domain Protein / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D007553:Isotope Labeling; D019169:Jurkat Cells; D008024:Ligands; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D019014:fas Receptor / Q000378:metabolism*; D000097868:Polo-like Kinases
D053181:Caspase 8; D053418:Death Domain Receptor Signaling Adaptor Proteins; D053200:Fas-Associated Death Domain Protein; D008024:Ligands; D010769:Phosphothreonine; D017346:Protein Serine-Threonine Kinases; D025521:Tumor Suppressor Proteins; D019014:fas Receptor; C505533:FADD protein, human; C486256:PLK3 protein, human; D000097868:Polo-like Kinases