Correlation of fragile histidine triad (Fhit) protein structural features with effector interactions and biological functions.
We have previously shown that Fhit tumor suppressor protein interacts with Hsp60 chaperone machinery and ferredoxin reductase (Fdxr) protein. Fhit-effector interactions are associated with a Fhit-dependent increase in Fdxr stability, followed by generation of reactive oxygen species and apoptosis induction under conditions of oxidative stress. To define Fhit structural features that affect interactions, downstream signaling, and biological outcomes, we used cancer cells expressing Fhit mutants with amino acid substitutions that alter enzymatic activity, enzyme substrate binding, or phosphorylation at tyrosine 114. Gastric cancer cell clones stably expressing mutants that do not bind substrate or cannot be phosphorylated showed decreased binding to Hsp60 and Fdxr and reduced mitochondrial localization. Expression of Fhit or mutants that bind interactor proteins results in oxidative damage and accumulation of cells in G(2)/M or sub-G(1) fractions after peroxide treatment; noninteracting mutants are defective in these biological effects. Gastric cancer clones expressing noncomplexing Fhit mutants show reduction of Fhit tumor suppressor activity, confirming that substrate binding, interaction with heat shock proteins, mitochondrial localization, and interaction with Fdxr are important for Fhit tumor suppressor function.
Pichiorri
Flavia
F
Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University and Comprehensive Cancer Center, Columbus, Ohio 43210, USA.
Okumura
Hiroshi
H
Nakamura
Tatsuya
T
Garrison
Preston N
PN
Gasparini
Pierluigi
P
Suh
Sung-Suk
SS
Druck
Teresa
T
McCorkell
Kelly A
KA
Barnes
Larry D
LD
Croce
Carlo M
CM
Huebner
Kay
K
D017766:Acid Anhydride Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D009154:Mutation / Q000235:genetics; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D023041:Xenograft Model Antitumor Assays; D000099170:Bis(5'-adenosyl)triphosphatase
D017766:Acid Anhydride Hydrolases; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D000099170:Bis(5'-adenosyl)triphosphatase