Antitumor antibiotic fostriecin covalently binds to cysteine-269 residue of protein phosphatase 2A catalytic subunit in mammalian cells.
Fostriecin is a phosphate monoester with excellent antitumor activity against mouse leukemia, and it is a potent inhibitor of protein phosphatase (PP) 2A. This compound has been predicted to covalently bind to the Cys269 residue of the PP2A catalytic subunit (PP2Ac) at the alpha,beta-unsaturated lactone via a conjugate addition reaction. However, this binding has not yet been experimentally proven. To confirm such binding, we synthesized biotin-labeled fostriecin (bio-Fos), which has an inhibitory activity against the proliferation of mouse leukemia cells. We showed that fostriecin directly binds to PP2Ac in HeLa S3 cells by pull-down assays using bio-Fos. Moreover, we directly demonstrated that fostriecin covalently binds to the Cys269 residue of PP2Ac by matrix assisted laser desorption/ionization time-of-flight mass spectrometry analysis. From these results, the inhibitory mechanism of fostriecin on PP2A activity is discussed.
Department of Applied Biological Science, Tokyo University of Science (RIKADAI), 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan.
Toshifumi
T
Takeuchi
Noriyuki
N
Takahashi
Kazutomo
K
Ishi
Tomoe
T
Kusayanagi
Kouji
K
Kuramochi
Fumio
F
Sugawara
D000475:Alkenes / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001665:Binding Sites / Q000502:physiology; D001667:Binding, Competitive / Q000502:physiology; D020134:Catalytic Domain / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D003545:Cysteine / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011090:Polyenes; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D011753:Pyrones / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017550:Spectroscopy, Fourier Transform Infrared
D000475:Alkenes; D000903:Antibiotics, Antineoplastic; D011090:Polyenes; D011753:Pyrones; D054648:Protein Phosphatase 2; D003545:Cysteine; C040313:fostriecin