NCBI Summary:
The protein encoded by this gene is a member of the cyclin-dependent protein kinase (CDK) family. CDK family members are highly similar to the gene products of Saccharomyces cerevisiae cdc28, and Schizosaccharomyces pombe cdc2, and are known to be important regulators of cell cycle progression. This kinase is a catalytic subunit of the protein kinase complex that is important for cell cycle G1 phase progression and G1/S transition. The activity of this kinase first appears in mid-G1 phase, which is controlled by the regulatory subunits including D-type cyclins and members of INK4 family of CDK inhibitors. This kinase, as well as CDK4, has been shown to phosphorylate, and thus regulate the activity of, tumor suppressor protein Rb.
Temporal Distribution of CDK4, CDK6, D-Type Cyclins, and p27 in Developing Mouse Oocytes Kohoutek J, et al .
Various molecular interactions not operating in other cell types are most likely required for mammalian oocytes to develop into fully competent eggs. This study seeks to initiate analyses of the potential oocyte-specific functions of regulators of G1/S progression, CDK4, CDK6, D-type cyclins, and p27, by first determining their expression patterns in growing and maturing mouse oocytes, and in mouse embryos early after fertilization. Western blot and immunofluorescence analyses on isolated oocytes were employed to evaluate both their levels and their localization. The data show that: (a) mouse oocytes contain significant amounts of all studied regulators; (b) their amounts and localization undergo dramatic changes as the oocytes grow, meiotically mature, and transit into embryogenesis; and (c) some regulators (CDK4, CDK6, cyclin D2, and p27) appear in unusual, most likely posttranslationally modified forms. These data distinguish G1/S regulators as the potential players in molecular processes that are important for oocytes to function normally.