GO:0097133 cyclin D3-CDK6 complex: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0097133 (cyclin D3-CDK6 complex) is a cellular_component defined as a protein complex of cyclin D3 and cyclin-dependent kinase 6 (CDK6).
• The complex is a serine/threonine kinase holoenzyme whose activity depends on cyclin D3 binding and is modulated by CDK inhibitors such as p27Kip1.
• Cyclin D3-CDK6 phosphorylates substrates including the retinoblastoma protein (RB) to drive G1/S transition, and also phosphorylates metabolic enzymes such as 6-phosphofructokinase (PFKP) and pyruvate kinase M2 (PKM2) to support cancer cell survival.
• Its kinase activity is reduced by antiestrogens in myeloma cells, linking the complex to endocrine therapy response.
• Cyclin D3 and CDK6 are differentially regulated in hepatocyte proliferation and in B and T lymphocyte proliferation.
• Dysregulation of the complex is implicated in cancers, including breast cancer and multiple myeloma, and in cell cycle checkpoint dysfunction in Parkinson's disease lymphoblasts.
Description
The cyclin D3-CDK6 complex (GO:0097133) is a cellular component consisting of the regulatory cyclin D3 and the catalytic cyclin-dependent kinase 6 (CDK6). Cyclins are characterized by periodicity in protein abundance throughout the cell cycle, and CDKs are serine/threonine protein kinases that become active upon binding to a cyclin partner. The cyclin D3-CDK6 holoenzyme therefore represents a cell-cycle-regulated kinase module that couples extracellular signals to phosphorylation of key substrates. Because CDK6 can pair with D-type cyclins, the cyclin D3-CDK6 complex is studied as a distinct entity with its own substrate preferences and regulatory inputs. Researchers care about GO:0097133 because it sits at the interface of cell cycle control and metabolism. Beyond canonical RB phosphorylation, the complex can phosphorylate metabolic enzymes to influence cancer cell survival. Its activity is sensitive to CDK inhibitors such as p27Kip1 and to antiestrogen treatment, making it a node for understanding drug response and resistance. The complex is also relevant to normal proliferative programs in hepatocytes and lymphocytes, where cyclin D3 and CDK6 are differentially regulated. This article summarizes the QuickGO definition, the structure and assembly of the complex, its molecular mechanism, the genes and proteins involved, disease links, and experimental methods including CRISPR-based models for studying cyclin D3-CDK6 biology.
cyclin D3-CDK6 complex At A Glance
| GO ID | GO:0097133 |
|---|---|
| GO term | cyclin D3-CDK6 complex |
| Ontology | cellular_component |
| Synonym | None listed in QuickGO |
| Major function | Serine/threonine kinase holoenzyme that phosphorylates substrates including RB and metabolic enzymes to regulate G1/S progression and cancer cell survival |
| Complex components | Cyclin D3 (regulatory subunit) and CDK6 (catalytic subunit) |
| Regulation | Modulated by CDK inhibitors such as p27Kip1 and by antiestrogen treatment |
| Disease relevance | Implicated in multiple myeloma, breast cancer, and cell cycle checkpoint dysfunction in Parkinson's disease lymphoblasts |
| Research methods | Kinase assays, co-immunoprecipitation, CRISPR knockout/knock-in, metabolic assays, and cell cycle analysis |
What Is GO:0097133?
GO:0097133 (cyclin D3-CDK6 complex) is a protein complex composed of cyclin D3 and cyclin-dependent kinase 6 (CDK6). Cyclins show periodic abundance through the cell cycle, and CDKs are serine/threonine kinases activated by binding to a cyclin regulatory partner. The complex is therefore a cyclin-CDK holoenzyme in which cyclin D3 provides regulatory and substrate-targeting functions while CDK6 provides catalytic kinase activity.
Why Is cyclin D3-CDK6 complex Important in Cell Biology?
The cyclin D3-CDK6 complex is important because it links cell cycle progression to metabolic reprogramming and to clinically relevant drug responses. Its kinase activity phosphorylates RB and other substrates to promote G1/S transition, and it can also phosphorylate metabolic enzymes such as PFKP and PKM2 to support cancer cell survival. In multiple myeloma, antiestrogens reduce cyclin D3/CDK6 kinase activity and induce G1 arrest, connecting the complex to endocrine therapy mechanisms. In lymphocytes, cyclin D3 and CDK6 cooperate with p27Kip1 to regulate proliferation, highlighting its role in immune cell expansion. In hepatocytes, cyclin D3 is differentially regulated during proliferation, indicating tissue-specific control. Finally, G1/S checkpoint dysfunction involving such complexes has been observed in Parkinson's disease lymphoblasts, suggesting relevance beyond oncology.
• Drives G1/S transition by phosphorylating RB and related substrates.
• Phosphorylates metabolic enzymes PFKP and PKM2 to support cancer cell survival.
• Mediates antiestrogen-induced G1 arrest in multiple myeloma cells.
• Regulates B cell proliferation in response to IL-2, IL-4, or IL-10.
• Cooperates with p27Kip1 in T cell proliferation control.
• Shows differential regulation of cyclin D3 during hepatocyte proliferation.
• Exhibits distinct substrate phosphorylation compared with D1-, E-, and A-type cyclin-CDK complexes.
• Is linked to G1/S checkpoint dysfunction in Parkinson's disease lymphoblasts.
• Represents a target for CDK4/6-directed therapeutic strategies.
• Provides a model for studying cyclin-CDK assembly and substrate specificity.
What Happens During cyclin D3-CDK6 complex?
Assembly of the cyclin D3-CDK6 holoenzyme
In simple terms: Cyclin D3 and CDK6 join together to form an active kinase machine.
The cyclin D3-CDK6 complex forms when cyclin D3 binds CDK6, converting CDK6 into an active serine/threonine kinase. This assembly is part of the broader cyclin D-CDK4/6 module that integrates growth signals with cell cycle entry. The complex can be detected by co-immunoprecipitation and kinase assays in cancer cell lines and primary cells.
Substrate phosphorylation and G1/S progression
In simple terms: The complex adds phosphate groups to target proteins to push cells into DNA synthesis.
Once assembled, cyclin D3-CDK6 phosphorylates substrates such as RB, contributing to G1/S transition. Differential phosphorylation of substrates by D1-, D3-, E-, and A-type cyclin-CDK complexes indicates that cyclin D3-CDK6 has distinct substrate preferences. This activity is central to cell cycle commitment and is often deregulated in cancer.
Metabolic substrate phosphorylation
In simple terms: The complex also tags metabolic enzymes to help cancer cells survive.
Beyond canonical cell cycle substrates, cyclin D3-CDK6 phosphorylates metabolic enzymes including PFKP and PKM2, thereby modulating glycolytic flux and supporting cancer cell survival. This metabolic function expands the biological role of the complex beyond proliferation and links it to tumor metabolism.
Regulation by CDK inhibitors and antiestrogens
In simple terms: Brake proteins and drugs can slow down or stop the complex.
The activity of cyclin D3-CDK6 is restrained by CDK inhibitors such as p27Kip1, which regulates T cell and B cell proliferation. In multiple myeloma cells, pure antiestrogens reduce cyclin D3/CDK6 kinase activity and induce G1 arrest, while apoptosis is mediated by endoplasmic reticulum-dependent caspases. These regulatory inputs determine whether cells proliferate or arrest.
Key Genes Involved in GO:0097133 cyclin D3-CDK6 complex
The following genes and proteins are central to the biology, regulation, and study of the cyclin D3-CDK6 complex (GO:0097133).
| Gene | Major Role | Research Relevance |
|---|---|---|
| CCND3 | Encodes cyclin D3, the regulatory subunit of the complex | Required for CDK6 activation and substrate targeting |
| CDK6 | Encodes the catalytic serine/threonine kinase subunit | Phosphorylates RB and metabolic enzymes |
| RB1 | Encodes the retinoblastoma protein, a key substrate | Phosphorylation by cyclin D3-CDK6 promotes G1/S transition |
| CDKN1B | Encodes p27Kip1, a CDK inhibitor | Regulates T cell and B cell proliferation by inhibiting cyclin-CDK complexes |
| PFKP | Encodes 6-phosphofructokinase, a glycolytic enzyme | Phosphorylated by cyclin D3-CDK6 to support cancer cell survival |
| PKM | Encodes pyruvate kinase M2, a glycolytic enzyme | Phosphorylated by cyclin D3-CDK6 to modulate metabolism |
| CDK4 | Encodes a related CDK that partners with D-type cyclins | Provides context for cyclin D3-CDK6 specificity |
| CCND1 | Encodes cyclin D1, a related regulatory subunit | Used in comparative studies of cyclin-CDK substrate specificity |
| CCNE1 | Encodes cyclin E, a related cyclin | Used in comparative kinase assays |
| CCNA2 | Encodes cyclin A, a related cyclin | Used in comparative kinase assays |
| PCAF | Encodes a transcriptional co-activator | Regulates CDK2 activity and is relevant to cyclin-CDK regulation |
| IL2 | Encodes interleukin-2 | Stimulates B cell proliferation involving cyclin D3 and p27 |
| IL4 | Encodes interleukin-4 | Stimulates B cell proliferation involving cyclin D3 and p27 |
| IL10 | Encodes interleukin-10 | Stimulates B cell proliferation involving cyclin D3 and p27 |
| CDKN1A | Encodes p21, a CDK inhibitor | General regulator of cyclin-CDK complexes |
| ESR1 | Encodes estrogen receptor alpha | Mediates antiestrogen effects on cyclin D3/CDK6 activity in myeloma |
| CCND2 | Encodes cyclin D2, a related D-type cyclin | Context for D-type cyclin redundancy |
| CDK2 | Encodes CDK2, a related kinase | Regulated by PCAF and relevant to G1/S control |
How Is cyclin D3-CDK6 complex Regulated?
The cyclin D3-CDK6 complex is regulated at multiple levels. CDK inhibitors such as p27Kip1 bind and inhibit cyclin-CDK complexes, thereby restraining T cell and B cell proliferation. In multiple myeloma cells, pure antiestrogens reduce the kinase activity of cyclin D3/CDK6 complexes, leading to G1 arrest, while apoptosis is mediated by endoplasmic reticulum-dependent caspases. The transcriptional co-activator PCAF regulates CDK2 activity, illustrating broader transcriptional control of cyclin-CDK modules. Differential regulation of cyclin D3 versus cyclin D1 in hepatocyte proliferation further indicates tissue-specific and stimulus-specific control of complex abundance and activity.
cyclin D3-CDK6 complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CCND3 | Multiple myeloma; antiestrogen-induced G1 arrest | Myeloma cell lines with CCND3 knockout or overexpression |
| CDK6 | Breast cancer; substrate phosphorylation | Breast cancer cell lines with CDK6 knockout or point mutation |
| CDKN1B | T cell and B cell proliferation disorders | Primary lymphocytes or Jurkat cells with CDKN1B knockout |
| PFKP | Cancer metabolism and survival | Cancer cell lines with PFKP phospho-mutant knock-in |
| PKM | Cancer metabolism and survival | Cancer cell lines with PKM2 phospho-mutant knock-in |
Multiple myeloma and endocrine therapy response
In multiple myeloma cells, pure antiestrogens induce G1 arrest by reducing the kinase activity of cyclin D3/CDK6 complexes, whereas apoptosis is mediated by endoplasmic reticulum-dependent caspases. This links the complex directly to endocrine therapy mechanisms and suggests that cyclin D3-CDK6 activity may influence drug sensitivity in hematologic malignancies.
Breast cancer and substrate phosphorylation
Cyclin D3-CDK6 complexes phosphorylate substrates in breast cancer cells, and comparative studies show differential phosphorylation of T-47D human breast cancer cell substrates by D1-, D3-, E-, and A-type cyclin-CDK complexes. These findings support a role for the complex in breast cancer cell cycle control and substrate specificity.
Cancer metabolism and survival
The cyclin D3-CDK6 kinase phosphorylates metabolic enzymes including PFKP and PKM2, and this metabolic function supports cancer cell survival. This positions the complex at the intersection of cell cycle regulation and tumor metabolism, with potential implications for metabolic targeting in cancer.
Neurodegeneration and cell cycle checkpoint dysfunction
G1/S cell cycle checkpoint dysfunction has been observed in lymphoblasts from sporadic Parkinson's disease patients, indicating that cell cycle regulatory complexes, including cyclin-CDK modules, may be altered in neurodegenerative contexts. This suggests broader relevance of the complex beyond oncology.
From cyclin D3-CDK6 complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of cyclin D3-CDK6 block G1/S transition? | CDK6 knockout cell lines |
| Does a specific phosphorylation site on RB mediate G1/S control? | RB1 point-mutation knock-in |
| Does cyclin D3-CDK6 phosphorylate metabolic enzymes in vivo? | PFKP or PKM2 phospho-mutant knock-in |
| How does p27Kip1 regulate cyclin D3-CDK6 in lymphocytes? | CDKN1B knockout or overexpression in T/B cells |
| Can antiestrogens inhibit cyclin D3-CDK6 activity? | Myeloma cell lines treated with antiestrogens |
| Is cyclin D3-CDK6 activity altered in Parkinson's disease? | Patient-derived lymphoblasts with cell cycle analysis |
How to Study the cyclin D3-CDK6 complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro kinase assay | Phosphorylation of substrates by cyclin D3-CDK6 | Comparing activity across treatments |
| Co-immunoprecipitation | Physical interaction between cyclin D3 and CDK6 | Confirming complex assembly |
| Flow cytometry | Cell cycle distribution | Detecting G1 arrest after antiestrogen treatment |
| Western blotting | Protein levels and phosphorylation status | Assessing RB phosphorylation |
| Metabolic flux assay | Glycolytic activity | Linking complex to cancer metabolism |
| CRISPR knockout | Loss-of-function effects | Testing requirement for cyclin D3 or CDK6 |
| Phospho-mutant knock-in | Site-specific phosphorylation effects | Dissecting substrate phosphorylation |
| RNA-seq | Transcriptional changes | Identifying downstream pathways |
Kinase assays and substrate phosphorylation
In vitro kinase assays using immunoprecipitated cyclin D3-CDK6 complexes can measure phosphorylation of substrates such as RB and metabolic enzymes. These assays are used to compare activity across cell types and treatments, including antiestrogen exposure in myeloma cells.
Co-immunoprecipitation and complex detection
Co-immunoprecipitation followed by western blotting can detect the assembly of cyclin D3 with CDK6 in cell lysates. This approach is essential for confirming that the complex exists in a given biological context and for assessing changes in complex abundance.
Cell cycle analysis
Flow cytometry and DNA content analysis can determine whether modulation of cyclin D3-CDK6 activity alters G1/S progression. Such methods are used to link complex activity to cell cycle arrest or proliferation.
Metabolic assays
Glycolytic flux measurements and metabolite profiling can assess the impact of cyclin D3-CDK6-mediated phosphorylation of PFKP and PKM2 on cancer cell metabolism. These assays connect the complex to metabolic reprogramming.
How CRISPR Can Be Used to Study GO:0097133 cyclin D3-CDK6 complex
Knockout
CRISPR knockout of CDK6 or CCND3 can abolish cyclin D3-CDK6 complex formation and activity, allowing researchers to test its requirement for G1/S transition and cancer cell survival. Knockout models are also useful for validating substrate phosphorylation in metabolic pathways.
Point Mutation
Point mutations can be introduced into CDK6 to disable kinase activity or into substrate phosphorylation sites (e.g., in RB1, PFKP, or PKM2) to test their functional relevance. Such models help distinguish catalytic activity from scaffolding functions.
Knock-in
Knock-in of tagged cyclin D3 or CDK6 enables affinity purification and interactome analysis of the complex. Tagged knock-in models also facilitate tracking complex localization and dynamics in live cells.
Overexpression
Overexpression of cyclin D3 and CDK6 can drive constitutive complex activity, mimicking oncogenic states and enabling studies of drug resistance and metabolic reprogramming. Overexpression models are useful for testing CDK4/6 inhibitors and antiestrogen responses.
How EDITGENE Supports cyclin D3-CDK6 complex Research
Researchers studying cyclin D3-CDK6 complex-related genes often need to determine whether a candidate gene is causally involved in complex assembly, substrate phosphorylation, or disease phenotypes. Rigorous causal testing requires precise genetic models that can knockout, mutate, tag, or overexpress the relevant genes in relevant cell types.
Contact EDITGENE today to design your custom CRISPR model for cyclin D3-CDK6 complex research.
Frequently Asked Questions About cyclin D3-CDK6 complex
What is the cyclin D3-CDK6 complex (GO:0097133)?
It is a protein complex consisting of cyclin D3 and cyclin-dependent kinase 6 (CDK6), a serine/threonine kinase holoenzyme that regulates cell cycle progression and metabolism.
What genes are involved in the cyclin D3-CDK6 complex?
The core genes are CCND3 (cyclin D3) and CDK6, with substrates and regulators including RB1, CDKN1B (p27Kip1), PFKP, and PKM.
What does the cyclin D3-CDK6 complex do?
It phosphorylates substrates such as RB to promote G1/S transition and metabolic enzymes such as PFKP and PKM2 to support cancer cell survival.
How is cyclin D3-CDK6 activity regulated?
It is inhibited by CDK inhibitors such as p27Kip1 and reduced by antiestrogen treatment in myeloma cells.
Is cyclin D3-CDK6 involved in cancer?
Yes, it is implicated in multiple myeloma and breast cancer, where its activity affects cell cycle progression and drug response.
What diseases are linked to cyclin D3-CDK6 dysfunction?
Multiple myeloma, breast cancer, and cell cycle checkpoint dysfunction in Parkinson's disease lymphoblasts have been associated with altered cyclin-CDK activity.
How can I study cyclin D3-CDK6 in the lab?
Common methods include kinase assays, co-immunoprecipitation, flow cytometry, metabolic assays, and CRISPR knockout or knock-in models.
What CRISPR models are available for cyclin D3-CDK6 research?
Knockout, point mutation, knock-in, tagged knock-in, and overexpression models can be generated for CCND3, CDK6, and related genes.
Does cyclin D3-CDK6 have metabolic functions?
Yes, it phosphorylates PFKP and PKM2 to modulate glycolysis and support cancer cell survival.
Where can I find validated cell models for cyclin D3-CDK6?
EDITGENE provides knockout, point-mutation, knock-in, overexpression, and library screening services for cyclin D3-CDK6-related genes.
Conclusion
The cyclin D3-CDK6 complex (GO:0097133) is a cyclin-CDK holoenzyme that integrates cell cycle control with metabolic regulation. Its ability to phosphorylate RB and metabolic enzymes such as PFKP and PKM2 makes it a key node in cancer cell survival and proliferation. Regulation by p27Kip1 and sensitivity to antiestrogens further highlight its therapeutic relevance. Studying this complex requires precise genetic models and functional assays. CRISPR-based knockout, point mutation, knock-in, and overexpression approaches, combined with kinase assays and metabolic profiling, provide a robust framework for dissecting cyclin D3-CDK6 biology in health and disease.
References
- 1. Wang H et al.. 2017. The metabolic function of cyclin D3-CDK6 kinase in cancer cell survival.. Nature 546(7658):426-430 PMID: 28607489
- 2. Mohapatra S et al.. 2001. p27Kip1 regulates T cell proliferation.. J Biol Chem 276(24):21976-83 PMID: 11297537
- 3. Gauduchon J et al.. 2008. Pure antiestrogen-induced G1-arrest in myeloma cells results from the reduced kinase activity of cyclin D3/CDK6 complexes whereas apoptosis is mediated by endoplasmic reticulum-dependent caspases.. Int J Cancer 122(9):2130-41 PMID: 18183592
- 4. Rickheim DG et al.. 2002. Differential regulation of cyclins D1 and D3 in hepatocyte proliferation.. Hepatology 36(1):30-8 PMID: 12085346
- 5. Sarcevic B et al.. 1997. Differential phosphorylation of T-47D human breast cancer cell substrates by D1-, D3-, E-, and A-type cyclin-CDK complexes.. J Biol Chem 272(52):33327-37 PMID: 9407125
- 6. Mateo F et al.. 2009. The transcriptional co-activator PCAF regulates cdk2 activity.. Nucleic Acids Res 37(21):7072-84 PMID: 19773423
- 7. Wagner EF et al.. 1998. A pivotal role of cyclin D3 and cyclin-dependent kinase inhibitor p27 in the regulation of IL-2-, IL-4-, or IL-10-mediated human B cell proliferation.. J Immunol 161(3):1123-31 PMID: 9686570
- 8. Esteras N et al.. 2015. G1/S Cell Cycle Checkpoint Dysfunction in Lymphoblasts from Sporadic Parkinson's Disease Patients.. Mol Neurobiol 52(1):386-98 PMID: 25182869
