Post-Translational Control of Retinoblastoma Protein Phosphorylation

The retinoblastoma tumor suppressor protein (pRB) functions through multiple mechanisms to serve as a tumor suppressor. pRB has been well characterized to be inactivated through phosphorylation by CDKs. pRB dephosphorylation and activation is a much less characterized aspect of pRB function. In this thesis, I detail work to study the post translational control of pRB phosphorylation. Here I present work detailing efforts to generate a gene targeted mouse which disrupts PP1 binding to the C-terminus of pRB, allowing for detailed study of the mechanisms of pRB dephosphorylation. This work also details an examination of acetylation in the C-terminus of pRB, which disrupts CDK phosphorylation of pRB. I generated a site specific antibody to examine K873/K874 acetylation, and carried out characterization of this set of post-translational modifications. This work highlights the complex mechanisms surrounding pRB phosphorylation state and regulation of pRB activation