title: The amelioration of renal damage in Skp2-deficient mice canceled by p27 Kip1 deficiency in Skp2-/- p27-/- mice.
abstract: SCF-Skp2 E3 ubiquitin ligase (Skp2 hereafter) targets several cell cycle regulatory proteins for degradation via the ubiquitin-dependent pathway. However, the target-specific physiological functions of Skp2 have not been fully elucidated in kidney diseases. We previously reported an increase in Skp2 in progressive nephropathy and amelioration of unilateral ureteral obstruction (UUO) renal injury associated with renal accumulation of p27 in Skp2(-/-) mice. However, it remains unclear whether the amelioration of renal injury in Skp2(-/-) mice is solely caused by p27 accumulation, since Skp2 targets several other proteins. Using Skp2(-/-)p27(-/-) mice, we investigated whether Skp2 specifically targets p27 in the progressive nephropathy mediated by UUO. In contrast to the marked suppression of UUO renal injury in Skp2(-/-) mice, progression of tubular dilatation associated with tubular epithelial cell proliferation and tubulointerstitial fibrosis with increased expression of collagen and α-smooth muscle actin were observed in the obstructed kidneys in Skp2(-/-)p27(-/-) mice. No significant increases in other Skp2 target proteins including p57, p130, TOB1, cyclin A and cyclin D1 were noted in the UUO kidney in Skp2(-/-) mice, while p21, c-Myc, b-Myb and cyclin E were slightly increased. Contrary to the ameliorated UUO renal injure by Skp2-deficiency, the amelioration was canceled by the additional p27-deficiency in Skp2(-/-)p27(-/-) mice. These findings suggest a pathogenic role of the reduction in p27 targeted by Skp2 in the progression of nephropathy in UUO mice.
authors.affiliation: Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Suzuki
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Fukasawa
authors.forename: Taro
authors.initials: T
authors.lastname: Misaki
authors.forename: Akashi
authors.initials: A
authors.lastname: Togawa
authors.forename: Naro
authors.initials: N
authors.lastname: Ohashi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kitagawa
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Kotake
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Niida
authors.forename: Keiko
authors.initials: K
authors.lastname: Nakayama
authors.forename: Keiichi I
authors.initials: KI
authors.lastname: Nakayama
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kitagawa
mesh_terms: D000818:Animals; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D005355:Fibrosis; D055786:Gene Knockout Techniques; D007674:Kidney Diseases / Q000150:complications / Q000378:metabolism*; D007684:Kidney Tubules / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D044786:S-Phase Kinase-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D014517:Ureteral Obstruction / Q000150:complications
chemical_list: D044786:S-Phase Kinase-Associated Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27