A single amino acid substitution results in a retinoblastoma protein defective in phosphorylation and oncoprotein binding.
We previously identified a small cell lung cancer cell line (NCI-H209) that expressed an aberrant, subphosphorylated form of the retinoblastoma protein RB1. Molecular analysis of RB1 mRNA from this cell line showed a mutation at exon 21 that led to a non-conservative amino acid substitution (cysteine to phenylalanine) at codon 706. Strong expression of mutant RB1 cDNA in the human cell line - endogenous RB1 deficiency was demonstrated. that this amino acid change is sufficient to inhibit phosphorylation. In addition, this substitution of cysteine for phenylalanine also resulted in the loss of RB1-binding monkey 40 large tumor virus and E1A-modifying egg protein adenovirus. These results confirm the importance of the sequences encoding exon 21 and suggest that the cysteine residue at codon 706 may play a role in meeting the specific protein adaptation requirement for protein-protein interactions. . The Gmail API returns two levels of error information: HTTP error ...