Retinoblastoma Protein, Cellular Biochemistry
Retinoblastoma protein is a 110 kDa nuclear phosphoprotein (tumor suppression). The gene locus maps to 13q14.1–q14.2. Retinoblastoma is an embryonic neoplasm of retinal origin. Young children with a germline mutation in one Rb1 allele have a 95 % chance of developing a retinoblastoma tumor in their eyes. Mutation in the Rb1 allele also predisposes patients to develop other tumors, such as osteosarcomas and fibrosarcomas. Almost two-thirds of the secondary tumors arising in patients with retinoblastoma are mesenchymal in origin. Most mutations in Rb1 lead to premature termination of translation.
pRb and Its Family Members
The pRb, p107, and p130 proteins form the “pocket protein” family that is crucial in cell-cycleregulation. pRb and p107/p130 have five domains of high conservation. pRb shares between 30 % and 35 % sequence identity with p107/p130. Most of the conserved sequences lie within the so-called pocket region (amino acid 379–792), which is composed...