Increase of cyclin B by overexpression of cystatin alpha.
Degradation of cyclin B was effectively suppressed when cells were treated with ALLN (N-acetylleucylleucylnorleucinal) which inhibits proteasome, calpain and cysteine proteinase cathepsins. In order to examine which protease degrades cyclin B, the effect of a cathepsin inhibitor, cystatin alpha, was investigated. The cystatin alpha gene was inserted into an inducible expression vector, pMSG, and transfected into NIH3T3 mouse fibroblasts. The expression of cystatin alpha was induced effectively in the transfected cells after treatment with dexamethasone. Overexpression of cystatin alpha resulted in an increase of the amount of cyclin B, suggesting that cysteine proteinase cathepsins might be involved in the degradation of cyclin B.
Hiwasa
T
T
Division of Biochemistry, Chiba Cancer Center Research Institute, Japan.
Ma
J
J
Ike
Y
Y
Katunuma
N
N
Sakiyama
S
S
D016475:3T3 Cells / Q000502:physiology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001483:Base Sequence; D016213:Cyclins / Q000378:metabolism*; D015891:Cystatins / Q000235:genetics*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D015870:Gene Expression / Q000502:physiology; D007976:Leupeptins / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D014162:Transfection
D000893:Anti-Inflammatory Agents; C070572:Csta protein, rat; D016213:Cyclins; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; C063261:acetylleucyl-leucyl-norleucinal; D003907:Dexamethasone