Comments by Stephen J. Elledge and J. Wade Harper, Baylor College of Medicine
"This paper describes the identification and characterization of the first human gene encoding a protein- p21Cip1-which functions to negatively regulate Cdks controlling cell-cycle entry," remarks Stephen Elledge, a professor of biochemistry at the Baylor College of Medicine and an investigator in the Howard Hughes Medical Institute there.
"Specific kinases called Cdk2 and Cdk4 are believed to play a critical role in helping a cell decide whether or not to enter into the cell cycle-the process in which a cell duplicates its DNA and organelles in order to form two new cells," explains Wade Harper, an associate professor of biochemistry at Baylor. "In this paper we discovered a novel protein that could bind tightly and specifically with these Cdks and block their ability to phosphorylate critical substrates.
"We now know that p21 is a member of a family ...
