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Updated: Aug 10, 2026
Analysis of Cell Cycle Position in Mammalian Cells
Published on: January 21, 2012
Retinoblastoma protein family in cell cycle and cancer: a review
M G Paggi1, A Baldi, F Bonetto
1Istituto Regina Elena per lo Studio e la Cura dei Tumori, Centro Ricerca Sperimentale, Rome, Italy.
Abstract:
Two genes, p107 and Rb2/p130, are strictly related to RB, the most investigated tumor suppressor gene, responsible for susceptibility to retinoblastoma. The products of these three genes, namely pRb, p107, and pRb2/p130 are characterized by a peculiar steric conformation, called "pocket," responsible for most of the functional interactions characterizing the activity of these proteins in the homeostasis of the cell cycle. The interest in these genes and proteins springs from their ability to regulate cell cycle processes negatively, being able, for example, to dramatically slow down neoplastic growth. So far, among these genes, only RB is firmly established to act as a tumor suppressor, because its lack-of-function is clearly involved in tumor onset and progression. It has been found deleted or mutated in most retinoblastomas and sarcomas, but its inactivation is likely to play a crucial role in other types of human cancers. The two other members of the family have been discovered more recently and are currently under extensive investigation. We review analogies and differences among the pocket protein family members, in an attempt to understand their functions in normal and cancer cells.
Insights
The RB, p107, and Rb2/p130 pocket proteins regulate the cell cycle. While RB is a known tumor suppressor, the functions of p107 and Rb2/p130 in normal and cancer cells require further investigation.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncology
Background:
- The retinoblastoma (RB) gene is a well-investigated tumor suppressor linked to retinoblastoma susceptibility.
- RB, p107, and Rb2/p130 proteins share a conserved
- domain crucial for cell cycle regulation.
- Dysregulation of these proteins is implicated in various human cancers.
Purpose of the Study:
- To review the analogies and differences between RB, p107, and Rb2/p130 pocket proteins.
- To elucidate the functions of these pocket proteins in both normal and cancerous cells.
- To understand their roles in cell cycle homeostasis and neoplastic growth regulation.
Main Methods:
- Literature review and comparative analysis of existing research on RB, p107, and Rb2/p130.
- Examination of protein structures and functional interactions.
- Analysis of genetic alterations and their correlation with tumor development.
Main Results:
- RB is confirmed as a tumor suppressor, with its inactivation linked to retinoblastomas and sarcomas.
- p107 and Rb2/p130, though structurally similar to RB, have functions that are still under extensive investigation.
- All three pocket proteins negatively regulate cell cycle progression, potentially inhibiting neoplastic growth.
Conclusions:
- The RB family of pocket proteins plays a critical role in cell cycle control.
- Further research is needed to fully understand the distinct and overlapping functions of p107 and Rb2/p130 in cancer.
- Comparative analysis highlights the importance of these proteins in maintaining cellular homeostasis and their potential as therapeutic targets.
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