MCF2 Cell Line Derived Transforming Sequence Like Protein (MCF2L)

The deduced 1,108-amino acid protein shares 87.5% identity with rat Ost. RT-PCR analysis detected high MCF2L expression in placenta, brain, and kidney, intermediate expression in prostate, lung, and liver, and low expression in heart, skeletal muscle, pancreas, thymus, ovary, and small intestine. No expression was detected in spleen and testis.

The DH and PH domains of Ost were required for transforming activity, and removal of an N-terminal domain increased Ost transforming ability. Purified rat Ost protein catalyzed guanine nucleotide exchange on RhoA (ARHA) and Cdc42, but not on any other Rho and Ras family members tested. Ost did not appear to associate with RhoA or Cdc42, but interacted specifically with the GTP-bound form of Rac1 .