Question

What does Rb stand for? Is Rb active or inactive in tumor cells?

Retinoblastoma Protein:

Inactive in Tumor Cells:

Tumor Suppressor:

Regulator of G1-S Checkpoint:

Answer 1

Retinoblastoma protein (Rb) is a tumor-suppressor protein that regulates the cell cycle and prevents uncontrolled cell division. In tumor cells, Rb is inactive and unable to perform its normal functions. It monitors cell size and blocks the production of proteins necessary for the G1/S transition, but when inactivated, the cell cycle progresses uncontrollably.

Step-by-step explanation:

Retinoblastoma protein (Rb) is a tumor-suppressor protein that is commonly found in many cells. It is part of a group of negative regulatory molecules that also includes p53 and p21. These proteins play a crucial role in regulating the cell cycle and preventing uncontrolled cell division.

In tumor cells, Rb is inactive or non-functional. Its normal function is to monitor cell size and bind to transcription factors, like E2F, to block the production of proteins necessary for the G1/S transition. However, when Rb is inactivated, the block is removed, allowing the cell to progress through the cell cycle uncontrollably.