Protein. E. coli BL21(DE3) (F-ompT gal dcm hsdSB (rB-mB-) λ (DE3) (Novagen) cells were transformed with recombinant plasmid, pET43.1-IRAS(10-120aa). Transformants were selected from ampicillin-containing Luria Bertani (LB) lates. Selected colonies were cultured in ampicillincontaining LB media. Isopropyl-β-D-thio galactopyranoside (IPTG) was added to a final concentration of 1 mM. The incubation was continued for 3 hours at 30 • C. Cells were harvested, mixed with lysis buffer (phosphate buffered saline [pH 7.3], 1.0 mM EDTA, 1.0 mM phenylmethylsulfonyl fluoride, 0.5 mg/mL lysozyme (Roche)), and sonicated. The high-speed supernatant which contained the pET43.1-IRAS(10-120aa) soluble protein fraction was loaded onto 10 mL Ni 2+ -NTA agarose columns. The fusion protein was eluted with lysis buffer with 400 mM imidazole. Eluted proteins were electrophoresed on SDS-PAGE gels. Expression yields were analyzed with the Quantity One quantitative software (Bio-Rad) based on relative band intensities of comassie blue stains. Purified proteins were detected with western blot using anti-His mAbs (Santa Cruz).