title: The retinoblastoma protein is phosphorylated during specific phases of the cell cycle.
abstract: p105-RB is the product of the retinoblastoma tumor suppressor gene. It is a nuclear phosphoprotein hypothesized to act as an inhibitor of cellular proliferation, yet surprisingly it is present in actively dividing cells. To look for changes in p105-RB that may regulate its activity during the cell cycle, we generated synchronized cell populations and followed their progression through the cell cycle. p105-RB is synthesized throughout the cycle, but is phosphorylated in a phase-specific manner. In the G0 and G1 phases of the cell cycle, an unphosphorylated species of the protein is the only detectable form, whereas in the S and G2/M phases, multiple phosphorylated species of p105-RB are detected.
authors.affiliation: Cold Spring Harbor Laboratory, New York 11724.
authors.forename: K
authors.initials: K
authors.lastname: Buchkovich
authors.forename: L A
authors.initials: LA
authors.lastname: Duffy
authors.forename: E
authors.initials: E
authors.lastname: Harlow
mesh_terms: D002453:Cell Cycle; D004261:DNA Replication; D005134:Eye Neoplasms / Q000235:genetics*; D005434:Flow Cytometry; D006367:HeLa Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007399:Interphase; D008938:Mitosis; D010750:Phosphoproteins / Q000096:biosynthesis / Q000378:metabolism*; D010766:Phosphorylation; D012175:Retinoblastoma / Q000235:genetics*; D016160:Retinoblastoma Protein; D013489:Suppression, Genetic
chemical_list: D010750:Phosphoproteins; D016160:Retinoblastoma Protein