Phospho-Rb (Thr356) Antibody

The retinoblastoma tumor suppressor protein Rb regulates cell proliferation by controlling progression through the restriction point within the G1-phase of the cell cycle (1). Rb has three functionally distinct binding domains and interacts with critical regulatory proteins including the E2F family of transcription factors, c-Abl tyrosine kinase, and proteins with a conserved LXCXE motif (2-4). Cell cycle-dependent phosphorylation by a CDK inhibits Rb target binding and allows cell cycle progression (5). Rb inactivation and subsequent cell cycle progression likely requires an initial phosphorylation by cyclin D-CDK4/6 followed by cyclin E-CDK2 phosphorylation (6). Specificity of different CDK/cyclin complexes has been observed in vitro (6-8) and cyclin D1 is required for Ser780 phosphorylation in vivo (9). 1.Sherr, C.J. (1996) Science 274, 1672-7. 2.Nevins, J.R. (1992) Science 258, 424-9. 3.Welch, P.J. and Wang, J.Y. (1993) Cell 75, 779-90. 4.Hu, Q.J. et al. (1990) EMBO J 9, 1147-55. 5.Knudsen, E.S. and Wang, J.Y. (1997) Mol Cell Biol 17, 5771-83. 6.Lundberg, A.S. and Weinberg, R.A. (1998) Mol Cell Biol 18, 753-61. 7.Connell-Crowley, L. et al. (1997) Mol Biol Cell 8, 287-301. 8.Kitagawa, M. et al. (1996) EMBO J 15, 7060-9. 9.Geng, Y. et al. (2001) Proc Natl Acad Sci USA 98, 194-9.