Which of the following statements is NOT true of the pRb protein? A)pRb is functionally inactive when it is hyperphosphorylated. B)pRb is mostly unphosphorylated during the G₀ phase of the cell cycle. C)pRb is growth-promoting during early G₁ phase. D)pRb phosphorylation is initiated by D-type cyclins and CDK4/6. E)pRb is functionally inactivated at the R point.

Question

Quizplus · Accepted Answer

pRb is growth-inhibitory during early GS phase, not growth-promoting. It functions to limit cell cycle progression until appropriate signals for cell division are present, which occurs at the R point. During this point, pRb is functionally inactivated through hyperphosphorylation.

Which of the Following Statements Is NOT True of the PRb