title: IL-1-induced ERK1/2 activation up-regulates p21(Waf1/Cip1) protein by inhibition of degradation via ubiquitin-independent pathway in human melanoma cells A375.
abstract: IL-1 inhibits the proliferation of human melanoma cells A375 by arresting the cell cycle at G0/G1 phase, which accompanies the increase of p21(Waf1/Cip1) (p21) protein. Here, we demonstrate that IL-1 induces the stabilization of p21 protein via ERK1/2 pathway. The degradation of p21 was inhibited by IL-1, however the ubiquitination level of p21 was not affected. In addition, the degradation of non-ubiquitinated form of lysine less mutant p21-K6R was also inhibited by IL-1, suggesting that IL-1 stabilized p21 protein via ubiquitin-independent pathway. Furthermore, the inhibition of p21 protein degradation was prevented by a selective inhibitor of ERK1/2 pathway, PD98059. These results suggest that IL-1-induced ERK1/2 activation leads to the up-regulation of p21 by inhibiting degradation via ubiquitin-independent pathway in human melanoma cells A375.
authors.affiliation: Department of Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Arakawa
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Hayashi
authors.forename: Saotomo
authors.initials: S
authors.lastname: Itoh
authors.forename: Takemasa
authors.initials: T
authors.lastname: Takii
authors.forename: Kikuo
authors.initials: K
authors.lastname: Onozaki
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000096:biosynthesis*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008545:Melanoma / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D007375:Interleukin-1; D025801:Ubiquitin; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3