title: Identification of DAPK as a scaffold protein for the LIMK/cofilin complex in TNF-induced apoptosis.
abstract: The role of cytoskeleton-associated proteins during TNF-induced apoptosis is not fully understood. A potential candidate kinase that might connect TNF signaling to actin reorganization is the death-associated protein kinase (DAPK). To identify new DAPK interaction partners in TNF-induced apoptosis, we performed a peptide array screen. We show that TNF-treatment enhanced the phosphorylation of LIMK at threonine508 and its downstream target cofilin at serine3 (p-cofilin(Ser3)). Modulation of DAPK activity and expression by DAPK inhibitor treatment, siRNA knockdown, and overexpression affected the phosphorylation of both proteins. We propose a 3D structural model where DAPK functions as a scaffold for the LIMK/cofilin complex and triggers a closer interaction of both proteins under TNF stimulation. Upon TNF a striking redistribution of LIMK, DAPK, and cofilin to the perinuclear compartment was observed. The pro-apoptotic DAPK/LIMK/cofilin multiprotein complex was abrogated in detached cells, indicating that its signaling was no longer needed if cells committed to apoptosis. P-cofilin(Ser3) was strongly accumulated in cells with condensed chromatin, pronounced membrane blebs and Annexin V up-regulation. From studying different cofilin(Ser3) mutants we suggest that p-cofilin(Ser3) is an indicator of TNF-induced apoptosis. Collectively, our findings identify a novel molecular cytoskeleton-associated mechanism in TNF-induced DAPK-dependent apoptosis.
authors.affiliation: Experimental Tumorpathology, Department of Pathology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Jelena
authors.initials: J
authors.lastname: Ivanovska
authors.forename: Alexandra
authors.initials: A
authors.lastname: Tregubova
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Mahadevan
authors.forename: Saritha
authors.initials: S
authors.lastname: Chakilam
authors.forename: Muktheshwar
authors.initials: M
authors.lastname: Gandesiri
authors.forename: Natalya
authors.initials: N
authors.lastname: Benderska
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ettle
authors.forename: Arndt
authors.initials: A
authors.lastname: Hartmann
authors.forename: Stephan
authors.initials: S
authors.lastname: Söder
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ziesché
authors.forename: Thomas
authors.initials: T
authors.lastname: Fischer
authors.forename: Lena
authors.initials: L
authors.lastname: Lautscham
authors.forename: Ben
authors.initials: B
authors.lastname: Fabry
authors.forename: Gabriela
authors.initials: G
authors.lastname: Segerer
authors.forename: Antje
authors.initials: A
authors.lastname: Gohla
authors.forename: Regine
authors.initials: R
authors.lastname: Schneider-Stock
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects*; D002448:Cell Adhesion / Q000187:drug effects; D051338:Cofilin 1 / Q000737:chemistry / Q000378:metabolism*; D064550:Death-Associated Protein Kinases / Q000378:metabolism*; D045325:HCT116 Cells; D006801:Humans; D054461:Lim Kinases / Q000378:metabolism*; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D051338:Cofilin 1; D046912:Multiprotein Complexes; D014409:Tumor Necrosis Factor-alpha; D064550:Death-Associated Protein Kinases; D054461:Lim Kinases
keywords: Apoptosis; Cofilin; DAPK; LIMK; TNF