Identification of novel PTEN-binding partners: PTEN interaction  with fatty acid binding protein FABP4.
PTEN is a tumor suppressor with dual protein and lipid-phosphatase activity, which is frequently deleted or mutated in many human advanced cancers. Recent studies have also demonstrated that PTEN is a promising target in type II diabetes and obesity treatment. Using C-terminal PTEN sequence in pEG202-NLS as bait, yeast two-hybrid screening on Mouse Embryo, Colon Cancer, and HeLa cDNA libraries was carried out. Isolated positive clones were validated by mating assay and identified through automated DNA sequencing and BLAST database searches. Sequence analysis revealed a number of PTEN-binding proteins linking this phosphatase to a number of different signaling cascades, suggesting that PTEN may perform other functions besides tumor-suppressing activity in different cell types. In particular, the interplay between PTEN function and adipocyte-specific fatty-acid-binding protein FABP4 is of notable interest. The demonstrable tautology of PTEN to FABP4 suggested a role for this phosphatase in the regulation of lipid metabolism and adipocyte differentiation. This interaction was further studied using coimmunoprecipitation and gel-filtration assays. Finally, based on Biacore assay, we have calculated the K(D) of PTEN-FABP4 complex, which is around 2.8 microM.
Gorbenko
O
O
Department of Cell Signaling, Institute of Molecular Biology and Genetics NASU, Kyiv, Ukraine.
Panayotou
G
G
Zhyvoloup
A
A
Volkova
D
D
Gout
I
I
Filonenko
V
V
D041721:3T3-L1 Cells; D000818:Animals; D002277:Carcinoma / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism; D004622:Embryo, Mammalian; D050556:Fatty Acid-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D015723:Gene Library; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000302:isolation & purification* / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D015003:Yeasts
C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; D011506:Proteins; D051059:PTEN Phosphohydrolase