title: Comparative Analysis of Two Gene-Targeting Approaches Challenges the Tumor-Suppressive Role of the Protein Kinase MK5/PRAK.
abstract: MK5 (MAPK-activated protein kinase 5) or PRAK (p38-regulated and -activated kinase) are alternative names for a serine/threonine protein kinase downstream to ERK3/4 and p38 MAPK. A previous gene targeting approach for MK5/PRAK (termed here MK5/PRAK-Δex8) revealed a seemingly tumor-suppressive role of MK5/PRAK in DMBA-induced one step skin carcinogenesis and Ras-induced transformation. Here we demonstrate that an alternative targeting strategy of MK5/PRAK (termed MK5/PRAK-Δex6) increased neither tumor incidence in the one step skin carcinogenesis model, nor Ras-induced transformation in primary cells. Interestingly, due to the targeting strategies and exon skipping both knockouts do not completely abolish the generation of MK5/PRAK protein, but express MK5/PRAK deletion mutants with different biochemical properties depending on the exon targeted: Targeting of exon 6 leads to expression of an unstable cytoplasmic catalytically inactive MK5/PRAK-Δex6 mutant while targeting of exon 8 results in a more stable nuclear MK5/PRAK-Δex8 mutant with residual catalytic activity. The different properties of the MK5/PRAK deletion mutants could be responsible for the observed discrepancy between the knockout strains and challenge the role of MK5/PRAK in p53-dependent tumor suppression. Further MK5/PRAK knockout and knock-in mouse strains will be necessary to assign a physiological function to MK5/PRAK in this model organism.
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Natalia
authors: N
authors: Ronkina
authors: Department of Dermatology, Aarhus University Hospital, Aarhus C, Denmark.
authors: Claus
authors: C
authors: Johansen
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Lisa
authors: L
authors: Bohlmann
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Juri
authors: J
authors: Lafera
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Manoj B
authors: MB
authors: Menon
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Christopher
authors: C
authors: Tiedje
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Kathrin
authors: K
authors: Laaß
authors: Department of Pharmacology, Yale University School of Medicine, New Haven, United States of America.
authors: Benjamin E
authors: BE
authors: Turk
authors: Department of Dermatology, Aarhus University Hospital, Aarhus C, Denmark.
authors: Lars
authors: L
authors: Iversen
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Alexey
authors: A
authors: Kotlyarov
authors: Department of Biochemistry, Hannover Medical School, Hannover, Germany.
authors: Matthias
authors: M
authors: Gaestel
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005091:Exons; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic; D055786:Gene Knockout Techniques / Q000379:methods*; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D055550:Protein Stability; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D012878:Skin Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; C111049:MAP-kinase-activated kinase 5; D017346:Protein Serine-Threonine Kinases