CCND3
CCND3 (cyclin D3, also called G1/S-specific cyclin-D3) is a member of the cyclin D subfamily that acts as a regulatory subunit of CDK4 and CDK6. It helps drive the G1/S transition of the cell cycle by phosphorylating members of the retinoblastoma protein family. Browse Assay Genie's current range of CCND3 research reagents below, or read on for the biology behind the target.
CCND3 is the regulatory component of the cyclin D3-CDK4 complex, which phosphorylates and inhibits retinoblastoma (RB) family proteins, including RB1, and so regulates the cell cycle at the G1/S transition. In early G1 phase the complex hypophosphorylates RB1. Phosphorylation of RB1 allows the transcription factor E2F to dissociate from the RB/E2F complex, permitting transcription of E2F target genes that are responsible for progression through G1. Cyclin D-CDK4 complexes are major integrators of mitogenic and antimitogenic signals.
Cyclin D3 also forms part of a ternary complex with CDK4 and CDKN1B, which is required for nuclear translocation and activity of the cyclin D-CDK4 complex. Separately from CDK4, it shows transcriptional coactivator activity with ATF5. The protein is found in the nucleus and the cytoplasm. According to NCBI Gene, it can also act as a regulatory subunit of CDK6, and CDK4 activity associated with this cyclin was reported to be necessary for progression through G2 phase into mitosis after UV radiation.
The CCND3 gene belongs to the highly conserved cyclin family, whose members show marked periodicity in protein abundance through the cell cycle. Different cyclins have distinct expression and degradation patterns, which help coordinate each mitotic event. HGNC places it in the cyclins gene group, alongside CCND1 and CCND2, and several transcript variants encoding different isoforms have been described. Mouse and rat both carry a Ccnd3 ortholog.
Cyclin D3-CDK4 activity governs RB1 phosphorylation and the G1/S transition, making CCND3 a central subject in studies of cell cycle control.
Phosphorylation of RB1 releases E2F and activates E2F target genes, so CCND3 is used to study this route into G1 progression.
Cyclin D-CDK4 complexes integrate mitogenic and antimitogenic signals, placing CCND3 at the point where extracellular cues meet the cell cycle machinery.
CCND3 acts as a transcriptional coactivator with ATF5 independently of CDK4, which opens questions about functions beyond kinase regulation.
CCND3 is the regulatory subunit of the cyclin D3-CDK4 complex, and it can also partner with CDK6. The complex phosphorylates RB family proteins such as RB1, releasing E2F and allowing transcription of genes needed to progress through G1 and into S phase.
The HGNC name is cyclin D3, and UniProt lists it as G1/S-specific cyclin-D3. No alternative symbols are recorded. NCBI Gene reports several transcript variants encoding different isoforms. Researchers often use "cyclin D3" and "CCND3" interchangeably when searching for an antibody or ELISA kit.
CCND3 belongs to the highly conserved cyclin family and the cyclin D subfamily, which also includes CCND1 and CCND2. Mouse and rat each have a Ccnd3 ortholog. Check the datasheet of any product for its validated reactivity.
Other D-type cyclins that regulate CDK4 and CDK6 and the G1/S transition, with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P30281; product specifications from Assay Genie datasheets.