GO:0000307 cyclin-dependent protein kinase holoenzyme complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000307 describes the cyclin-dependent protein kinase (CDK) holoenzyme complex, a cellular component composed of a catalytic CDK subunit bound to a regulatory cyclin partner [1,5].
• The CDK holoenzyme is the active form that phosphorylates substrates controlling cell-cycle progression and transcription [1,2].
• Assembly requires cyclin binding, which triggers conformational changes and activating phosphorylation by CDK-activating kinase (CAK).
• Dysregulation of CDK holoenzymes is linked to cancer, where cyclin D1 accumulation and CDK4/6 activity drive proliferation [6,8].
• Key components include CDK1, CDK2, CDK4, CDK6, CDK7, CDK8, CDK9 and cyclins A, B, C, D, E, H, K, T [1,4,5].
• CRISPR knockout, point mutation, knock-in and overexpression models enable precise dissection of CDK holoenzyme function in disease.
Description
The cyclin-dependent protein kinase holoenzyme complex (GO:0000307) is a cellular component defined as an enzyme complex containing a kinase catalytic subunit associated with a regulatory cyclin partner [1,5]. This holoenzyme is the functional unit that drives phosphorylation of key substrates involved in cell-cycle transitions and transcriptional regulation [1,2]. Researchers study this complex because its activity is essential for normal proliferation and its misregulation is a hallmark of many cancers [6,8]. The complex was first characterized through the identification of cyclin C/Cdk8 and human CDK8 as a putative partner for cyclin C [1,5]. Subsequent work showed that CDK4 activation requires association with a MO15-associated kinase, now known as CDK7, highlighting the layered regulation of holoenzyme assembly. Understanding the composition, assembly and regulation of GO:0000307 is therefore central to cell-cycle biology and oncology [2,6].
cyclin-dependent protein kinase holoenzyme complex At A Glance
| GO ID | GO:0000307 |
|---|---|
| GO term | cyclin-dependent protein kinase holoenzyme complex |
| Ontology | cellular_component |
| Synonym | CDK holoenzyme |
| Major function | Phosphorylation of substrates controlling cell-cycle progression and transcription [1,2] |
| Key subunits | Catalytic CDK and regulatory cyclin [1,5] |
| Assembly requirement | Cyclin binding and activating phosphorylation by CAK |
| Disease relevance | Cancer, including cyclin D1-dependent kinase dysregulation [6,8] |
| Research models | CRISPR KO, point mutation, knock-in, overexpression |
What Is GO:0000307?
GO:0000307, cyclin-dependent protein kinase holoenzyme complex, is a cellular component ontology term describing an enzyme complex in which a catalytic cyclin-dependent kinase (CDK) subunit is bound to a regulatory cyclin protein [1,5]. The cyclin partner provides substrate specificity and activates the kinase, while the CDK subunit carries the catalytic activity. This holoenzyme represents the active form of CDKs and is distinct from free monomeric CDK or cyclin subunits.
Why Is cyclin-dependent protein kinase holoenzyme complex Important in Cell Biology?
The CDK holoenzyme complex is important because it is the minimal functional unit that executes phosphorylation events required for cell-cycle progression and gene expression [1,2]. Its activity is tightly controlled by cyclin availability, post-translational modifications and regulatory proteins such as Hsc70, which governs cyclin D1 accumulation and cyclin D1-dependent kinase activity. Disruption of this complex leads to uncontrolled proliferation, making it a major target for cancer therapy and a focus of cell-cycle research.
• Controls cell-cycle transitions through phosphorylation of retinoblastoma protein and other substrates [2,6].
• Regulates transcription via CDK8/cyclin C and CDK9/cyclin T complexes [1,5].
• Cyclin D1-dependent kinase activity is regulated by Hsc70, linking proteostasis to proliferation.
• CDK4 activation requires MO15-associated kinase (CDK7), a key regulatory step.
• Dysregulation is implicated in cancer through histone acetylation and cell-cycle alterations.
• Telomere maintenance and structure are influenced by cell-cycle regulation.
• Serves as a target for small-molecule inhibitors in oncology [6,8].
• Provides a model for studying protein-protein interactions and substrate recognition.
• Relevant to osteosarcoma tumor microenvironment and metastasis.
• Enables CRISPR-based functional genomics of CDK-cyclin pairs.
What Happens During cyclin-dependent protein kinase holoenzyme complex?
Cyclin Binding and Holoenzyme Assembly
In simple terms: A cyclin protein attaches to a CDK enzyme to form the active complex.
The formation of the CDK holoenzyme begins with the binding of a regulatory cyclin to a catalytic CDK subunit [1,5]. This interaction induces conformational changes that partially activate the kinase and expose the substrate-binding site. For example, cyclin C binds to CDK8 to form a functional kinase complex involved in transcription [1,5].
Activating Phosphorylation by CAK
In simple terms: Another kinase adds a phosphate to the CDK to fully turn it on.
Full activation of the CDK holoenzyme often requires phosphorylation of a conserved threonine residue in the T-loop by CDK-activating kinase (CAK), which includes CDK7. This step is essential for CDK4 activation and subsequent substrate phosphorylation.
Substrate Recognition and Phosphorylation
In simple terms: The active complex finds and tags target proteins with phosphate groups.
Once assembled and activated, the CDK holoenzyme recognizes specific substrates through interactions mediated by the cyclin subunit and additional docking motifs. Phosphorylation of substrates such as the retinoblastoma protein triggers cell-cycle progression.
Regulation by Hsc70 and Cyclin D1
In simple terms: A chaperone protein controls how much cyclin D1 is available to form active complexes.
Hsc70 regulates the accumulation of cyclin D1 and consequently the activity of cyclin D1-dependent protein kinase. This chaperone-mediated control links protein folding and degradation pathways to CDK holoenzyme function.
Key Genes Involved in GO:0000307 cyclin-dependent protein kinase holoenzyme complex
The following genes encode core components and regulators of the cyclin-dependent protein kinase holoenzyme complex (GO:0000307).
| Gene | Major Role | Research Relevance |
|---|---|---|
| CDK1 | Catalytic subunit of M-phase CDK holoenzyme | Cell-cycle progression, mitosis |
| CDK2 | Catalytic subunit with cyclin E/A | G1/S transition, DNA replication |
| CDK4 | Catalytic subunit with cyclin D | G1 progression, cancer target [4,6] |
| CDK6 | Catalytic subunit with cyclin D | G1 progression, cancer target |
| CDK7 | CAK catalytic subunit, activates CDKs | T-loop phosphorylation |
| CDK8 | Catalytic subunit with cyclin C | Transcriptional regulation [1,5] |
| CDK9 | Catalytic subunit with cyclin T | Transcription elongation |
| CCNA2 | Regulatory cyclin for CDK2 | S-phase and mitosis |
| CCNB1 | Regulatory cyclin for CDK1 | Mitosis |
| CCNC | Regulatory cyclin for CDK8 | Transcription [1,5] |
| CCND1 | Regulatory cyclin for CDK4/6 | G1 progression, cancer |
| CCNE1 | Regulatory cyclin for CDK2 | G1/S transition |
| CCNH | Regulatory cyclin for CDK7 | CAK complex |
| CCNK | Regulatory cyclin for CDK9 | Transcription elongation |
| CCNT1 | Regulatory cyclin for CDK9 | Transcription elongation |
| HSPA8 | Hsc70 chaperone regulating cyclin D1 | Cyclin D1 accumulation |
| RB1 | Substrate of CDK holoenzyme | Cell-cycle checkpoint |
How Is cyclin-dependent protein kinase holoenzyme complex Regulated?
The activity of the cyclin-dependent protein kinase holoenzyme complex is regulated at multiple levels. Cyclin binding is the primary step, as cyclin levels fluctuate during the cell cycle [1,5]. Activating phosphorylation by CAK (CDK7/cyclin H) is required for full kinase activity. Inhibitory phosphorylation and CDK inhibitors also modulate activity. Additionally, chaperones such as Hsc70 control cyclin D1 accumulation and thus cyclin D1-dependent kinase activity. Histone acetylation and cell-cycle progression are interconnected, influencing CDK holoenzyme function in cancer.
cyclin-dependent protein kinase holoenzyme complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CCND1 | Breast cancer, lymphoma | Knockout or overexpression in cancer cell lines |
| CDK4 | Melanoma, breast cancer | Point mutation (kinase-dead) knock-in |
| CDK6 | Leukemia, lymphoma | CRISPR knockout in hematopoietic cells |
| CDK8 | Colorectal cancer | Knock-in of tagged CDK8 for interaction studies [1,5] |
| HSPA8 | Cancer, proteostasis | Knockout to assess cyclin D1 levels |
Cancer
Dysregulation of CDK holoenzymes is a hallmark of cancer. Cyclin D1 overexpression and CDK4/6 hyperactivity drive uncontrolled proliferation in many tumors [6,8]. Hsc70-mediated regulation of cyclin D1 accumulation further links proteostasis to oncogenesis. Targeting CDK4/6 has become a standard therapeutic strategy in breast cancer and other malignancies.
Osteosarcoma
Single-cell RNA sequencing has revealed communications between tumor microenvironment components and tumor metastasis in osteosarcoma, implicating cell-cycle-related pathways. CDK holoenzyme components may influence osteosarcoma progression and metastasis.
Telomere and Genome Stability
Telomere structure and function are regulated in a cell-cycle-dependent manner, and CDK holoenzymes contribute to this regulation. Disruption of CDK activity can lead to telomere dysfunction and genome instability.
From cyclin-dependent protein kinase holoenzyme complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does CDK4 kinase activity drive proliferation? | Point mutation (kinase-dead) knock-in |
| What is the role of cyclin D1 in tumor growth? | Overexpression or knockout in cancer cells |
| How does CDK8 regulate transcription? | Tagged knock-in for ChIP-seq [1,5] |
| Is CDK7 required for CAK activity? | CRISPR knockout of CDK7 |
| How does Hsc70 affect cyclin D1 accumulation? | Knockout of HSPA8 |
| What genes interact with CDK holoenzymes? | CRISPR library screening |
How to Study the cyclin-dependent protein kinase holoenzyme complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Co-IP/MS | Protein interactions | Identify cyclin-CDK partners |
| Kinase assay | Phosphorylation activity | Validate activating mutations |
| CRISPR screen | Gene essentiality | Find modifiers of CDK function |
| scRNA-seq | Gene expression heterogeneity | Tumor microenvironment analysis |
| Western blot | Protein levels | Cyclin D1 accumulation |
| ChIP-seq | DNA binding | CDK8/cyclin C transcriptional targets [1,5] |
| Flow cytometry | Cell-cycle distribution | Assess proliferation changes |
| Telomere FISH | Telomere length | Genome stability |
Co-immunoprecipitation and Mass Spectrometry
Co-immunoprecipitation followed by mass spectrometry can identify cyclin-CDK pairs and associated proteins in the holoenzyme complex. This approach reveals subunit composition and dynamic interactions.
Kinase Activity Assays
In vitro kinase assays using recombinant CDK-cyclin complexes and substrate peptides measure catalytic activity and the effects of mutations. Such assays are essential for validating point mutations.
CRISPR Screening
Genome-wide CRISPR knockout screens can identify genes that modulate CDK holoenzyme function or resistance to CDK inhibitors. This method links genotype to phenotype at scale.
Single-Cell RNA Sequencing
Single-cell RNA sequencing reveals expression patterns of CDK and cyclin genes across cell populations, as demonstrated in osteosarcoma microenvironment studies. This helps identify cell-type-specific dependencies.
How CRISPR Can Be Used to Study GO:0000307 cyclin-dependent protein kinase holoenzyme complex
Knockout
CRISPR knockout of CDK or cyclin genes abolishes holoenzyme formation and function, enabling loss-of-function studies. For example, knocking out CDK4 or CDK6 reduces proliferation in cancer cell lines.
Point Mutation
Introducing kinase-dead or activating point mutations in CDK genes allows precise dissection of catalytic activity versus scaffolding functions. Such models are valuable for drug resistance studies.
Knock-in
Tagged knock-in of CDK8 or cyclin C with epitope tags facilitates affinity purification and ChIP-seq to map genomic binding sites [1,5]. This approach preserves endogenous regulation [1,5].
Overexpression
Overexpression of cyclin D1 or CDK4 mimics oncogenic states and can transform cells, providing models for cancer research. Overexpression systems also help study stoichiometry of holoenzyme assembly.
How EDITGENE Supports cyclin-dependent protein kinase holoenzyme complex Research
Researchers studying cyclin-dependent protein kinase holoenzyme complex-related genes often need to determine whether a candidate gene is causally involved in cell-cycle regulation or disease. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for cyclin-dependent protein kinase holoenzyme complex research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CDKN1A Knockout HEK293 Cell Line | EDJ-KQ129 | Human | 1026 | Details Get a Quote |
| CCND1 Knockout HEK293 Cell Line | EDC07534 | Human | 595 | Details Get a Quote |
| CCND3 Knockout HEK293 Cell Line | EDJ-KQ285 | Human | 896 | Details Get a Quote |
| CCND2 Knockout HEK293 Cell Line | EDJ-KQ884 | Human | 894 | Details Get a Quote |
| CDK13 Knockout HEK293 Cell Line | EDJ-KQ1111 | Human | 8621 | Details Get a Quote |
| CDK2 Knockout HEK293 Cell Line | EDC07797 | Human | 1017 | Details Get a Quote |
| CCNB2 Knockout HEK293 Cell Line | EDJ-KQ1532 | Human | 9133 | Details Get a Quote |
| CCNB3 Knockout HEK293 Cell Line | EDJ-KQ1533 | Human | 85417 | Details Get a Quote |
| CCNG2 Knockout HEK293 Cell Line | EDJ-KQ1534 | Human | 901 | Details Get a Quote |
| CDK16 Knockout HEK293 Cell Line | EDJ-KQ2177 | Human | 5127 | Details Get a Quote |
| CDK17 Knockout HEK293 Cell Line | EDJ-KQ2344 | Human | 5128 | Details Get a Quote |
| CCNL2 Knockout HEK293 Cell Line | EDC90276 | Human | 81669 | Details Get a Quote |
| CCNI Knockout HEK293 Cell Line | EDJ-KQ3086 | Human | 10983 | Details Get a Quote |
| CCNG1 Knockout HEK293 Cell Line | EDJ-KQ3523 | Human | 900 | Details Get a Quote |
| CDK15 Knockout HEK293 Cell Line | EDJ-KQ3594 | Human | 65061 | Details Get a Quote |
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Frequently Asked Questions About cyclin-dependent protein kinase holoenzyme complex
What is GO:0000307?
GO:0000307 is the Gene Ontology term for cyclin-dependent protein kinase holoenzyme complex, a cellular component consisting of a catalytic CDK bound to a regulatory cyclin [1,5].
What genes are involved in cyclin-dependent protein kinase holoenzyme complex?
Key genes include CDK1, CDK2, CDK4, CDK6, CDK7, CDK8, CDK9 and cyclins A, B, C, D, E, H, K, T [1,4,5].
What is the function of CDK holoenzyme?
It phosphorylates substrates to control cell-cycle progression and transcription [1,2].
How is the CDK holoenzyme activated?
Cyclin binding and activating phosphorylation by CAK (CDK7) are required for full activity.
What diseases are associated with CDK holoenzyme dysregulation?
Cancer, including breast cancer and osteosarcoma, as well as genome instability [3,6,8].
What is the role of cyclin D1 in cancer?
Cyclin D1 accumulation, regulated by Hsc70, drives cyclin D1-dependent kinase activity and proliferation.
How can CRISPR be used to study CDK holoenzymes?
CRISPR knockout, point mutation, knock-in and overexpression models enable functional dissection [3,4].
What methods study CDK holoenzyme composition?
Co-immunoprecipitation, mass spectrometry and kinase assays are commonly used [2,4].
Is CDK8 part of the CDK holoenzyme complex?
Yes, CDK8 binds cyclin C to form a transcriptional CDK holoenzyme [1,5].
What is the relationship between CDK holoenzyme and telomeres?
Cell-cycle regulation by CDKs influences telomere structure and function.
Conclusion
The cyclin-dependent protein kinase holoenzyme complex (GO:0000307) is a central cellular component that integrates cyclin availability with catalytic CDK activity to drive cell-cycle progression and transcription [1,2]. Its dysregulation is implicated in cancer and other diseases, making it a prime target for therapeutic intervention [6,8]. Advances in CRISPR-based models and single-cell technologies continue to illuminate the precise roles of individual CDK-cyclin pairs [3,4]. EDITGENE provides the tools to accelerate this research through custom gene editing and screening services.
References
- 1. Leclerc V et al.. 1996. The cyclin C/Cdk8 kinase.. Prog Cell Cycle Res 2:197-204 PMID: 9552396
- 2. Cuomo ME et al.. 2011. Cyclin-cyclin-dependent kinase regulatory response is linked to substrate recognition.. J Biol Chem 286(11):9713-25 PMID: 21233209
- 3. Li J et al.. 2024. Single-cell RNA sequencing reveals the communications between tumor microenvironment components and tumor metastasis in osteosarcoma.. Front Immunol 15:1445555 PMID: 39324133
- 4. Matsuoka M et al.. 1994. Activation of cyclin-dependent kinase 4 (cdk4) by mouse MO15-associated kinase.. Mol Cell Biol 14(11):7265-75 PMID: 7935441
- 5. Tassan JP et al.. 1995. Identification of human cyclin-dependent kinase 8, a putative protein kinase partner for cyclin C.. Proc Natl Acad Sci U S A 92(19):8871-5 PMID: 7568034
- 6. Diehl JA et al.. 2003. Hsc70 regulates accumulation of cyclin D1 and cyclin D1-dependent protein kinase.. Mol Cell Biol 23(5):1764-74 PMID: 12588994
- 7. Lu W et al.. 2013. Telomeres-structure, function, and regulation.. Exp Cell Res 319(2):133-41 PMID: 23006819
- 8. Wang C et al.. 2001. Histone acetylation and the cell-cycle in cancer.. Front Biosci 6:D610-29 PMID: 11282573
