NFKB Inhibitor Interacting Ras Like Protein 2 (NKIRAS2)

One molecule identified was kappa-B-Ras1. Using the sequence of kappa-B-Ras1, Fenwick et al. (2000) screened expressed sequence tag (EST) databases and identified a related protein that they named kappa-B-Ras2. The 191-amino acid kappa-B-Ras2 protein has 71% identity to kappa-B-Ras1. In vitro translation revealed a protein of about 22 kD. Kappa-B-Ras2 is widely expressed and is encoded by a mRNA of 2.5 kb. Kappa-B-Ras2 interacts with the PEST domain of I-kappa-B-alpha and I-kappa-B-beta and decreases their rate of degradation. In cells, kappa-B-Ras proteins are associated only with the NF-kappa-B:I-kappa-B-beta complexes; Fenwick et al. (2000) suggested that therefore this may provide an explanation for the slower rate of degradation of I-kappa-B-beta compared with I-kappa-B-alpha.