CDC123 Human

What is CDC123 and what is its primary function in cellular processes?

CDC123 is a cell division cycle protein that plays a crucial role in S phase entry of the cell cycle. It functions as a regulator of cellular proliferation and is required for translation initiation through facilitating the biogenesis of eukaryotic initiation factor 2 (eIF2) . The protein is encoded by the CDC123 gene located on chromosome 10 in humans and has been implicated in both normal cellular homeostasis and disease pathogenesis .

Where is CDC123 expressed in human tissues and at what levels?

CDC123 displays a broad expression pattern across multiple human tissues. It is expressed in spleen, thymus, prostate, testis, ovary, small intestine, colon, and leukocytes, with the highest expression observed in testis . This wide distribution suggests CDC123 has fundamental cellular functions across diverse tissue types, though its tissue-specific roles may vary.

What are the recommended methods for purifying recombinant CDC123?

Recombinant CDC123 can be efficiently produced in E. coli expression systems. For optimal purification, researchers should:

• Express the protein with an N-terminal His-tag for affinity purification

• Use proprietary chromatographic techniques for high-purity isolation

• Maintain the protein in a solution containing 20mM Tris-HCl buffer (pH8.0), 20% glycerol, 0.1M NaCl, and 2mM DTT

• Verify purity via SDS-PAGE (expected >90% purity)

• Store the purified protein (0.5mg/ml) at 4°C for short-term use (2-4 weeks) or at -20°C with carrier protein (0.1% HSA or BSA) for long-term storage

This approach yields high-quality protein suitable for biochemical and functional studies.

How can researchers effectively study CDC123 in cancer models?

To investigate CDC123 in cancer contexts, researchers should consider:

• Expression analysis:

  • Assess CDC123 levels in cancer vs. normal tissues

  • Correlate expression with clinical outcomes and prognosis

• Functional studies:

  • Use siRNA/shRNA for CDC123 knockdown in cancer cell lines

  • Evaluate effects on proliferation, invasion, and migration

  • Perform cell cycle analysis to identify phase-specific effects (particularly G0/G1)

• Mechanistic investigations:

  • Examine interactions with regulatory proteins (e.g., USP9X)

  • Analyze changes in cell cycle-related gene expression

  • Employ rescue experiments by overexpressing CDC123 following inhibitor treatment

Studies in breast cancer and hepatocellular carcinoma have successfully employed these approaches to establish CDC123's oncogenic properties .

What is CDC123's specific role in cell cycle progression?

CDC123 plays a critical role in cell cycle regulation, particularly in the G1/S transition. Research demonstrates that:

• CDC123 is required for S phase entry

• Knockdown of CDC123 results in accumulation of cells in the G0/G1 phase

• Its depletion alters the expression of cell cycle-related genes

• The protein functions as a positive regulator of cellular proliferation

This evidence positions CDC123 as a key facilitator of cell cycle progression, making it particularly relevant in cancer research where dysregulated cell cycling is a hallmark.

How does post-translational modification regulate CDC123 function?

Post-translational modifications, particularly ubiquitination/deubiquitination, play a crucial role in regulating CDC123 stability and function:

• K48-linked ubiquitination at the K308 site targets CDC123 for proteasomal degradation

• The deubiquitinase USP9X physically interacts with CDC123 and removes these ubiquitin modifications

• USP9X-mediated deubiquitination stabilizes CDC123, preventing its degradation

• CDC123 expression positively correlates with USP9X levels in breast cancer cells

• Treatment with USP9X inhibitor WP1130 (Degrasyn) decreases CDC123 levels and arrests cells in G0/G1 phase

This regulatory mechanism represents a potential therapeutic vulnerability in CDC123-dependent cancers.

What evidence links CDC123 to breast cancer, and what are the underlying mechanisms?

Multiple lines of evidence establish CDC123's role in breast cancer:

• CDC123 is highly expressed in breast cancer cells compared to normal tissue

• High CDC123 expression correlates with poor prognosis in breast cancer patients

• Knockdown of CDC123 significantly impairs breast cancer cell proliferation

• Mechanistically, CDC123 promotes breast carcinogenesis through:

  • Regulation of cell cycle progression

  • Altered expression of cell cycle-related genes

  • The USP9X/CDC123 axis that stabilizes CDC123 protein levels

These findings suggest CDC123 as a potential prognostic marker and therapeutic target in breast cancer.

How does CDC123 contribute to hepatocellular carcinoma (HCC) progression?

CDC123 promotes hepatocellular carcinoma malignant progression through several mechanisms:

• CDC123 knockdown in HCC cell lines significantly inhibits:

  • Cellular proliferation

  • Invasion capacity

  • Migration potential

• CDC123 appears to exert its effects in HCC by regulating CDKAL1, another protein implicated in cancer progression

• The CDC123-CDKAL1 regulatory axis represents a potential intervention point for HCC therapy

These findings expand CDC123's oncogenic role beyond breast cancer to liver malignancies.

What is the connection between CDC123 genetic variants and metabolic disorders?

Genome-wide association studies have identified CDC123 as a susceptibility locus for type 2 diabetes:

• Genetic variants near or within CDC123 have been associated with:

  • Altered insulin response

  • Increased risk of type 2 diabetes in diverse populations, including Chinese Hans

  • Potential metabolic dysregulation

• CDC123 may functionally interact with CDKAL1, another diabetes-associated gene, suggesting shared or complementary pathways in metabolic regulation

The precise molecular mechanisms linking CDC123 variants to diabetes pathophysiology remain under investigation.

How can researchers investigate the USP9X-CDC123 axis in cancer models?

To study the USP9X-CDC123 regulatory pathway:

• Protein interaction studies:

  • Co-immunoprecipitation to confirm physical interaction

  • Proximity ligation assays for in situ visualization of interaction

  • Domain mapping to identify specific interaction regions

• Deubiquitination analysis:

  • In vitro deubiquitination assays with recombinant USP9X and ubiquitinated CDC123

  • Mass spectrometry to verify K308 as the critical ubiquitination site

  • Ubiquitin-linkage specific antibodies to confirm K48-linkage

• Functional analysis:

  • USP9X inhibition with WP1130 (Degrasyn) to assess CDC123 stability

  • CDC123 overexpression to rescue phenotypes induced by USP9X inhibition

  • Combined manipulation of both proteins to establish epistatic relationships

This comprehensive approach can clarify how USP9X-mediated deubiquitination of CDC123 contributes to cancer progression.

What experimental strategies can address the relationship between CDC123 and CDKAL1?

To investigate CDC123-CDKAL1 interactions in disease contexts:

• Expression correlation:

  • Analyze co-expression patterns in normal and disease tissues

  • Determine whether CDC123 manipulation affects CDKAL1 levels and vice versa

• Pathway analysis:

  • Conduct CDC123 knockdown followed by transcriptomic/proteomic analysis

  • Identify whether CDKAL1-related pathways are affected by CDC123 manipulation

  • Perform pathway enrichment analysis to identify shared molecular networks

• Genetic approaches:

  • Create double knockout/knockdown models of CDC123 and CDKAL1

  • Assess phenotypic differences compared to single gene manipulations

  • Conduct genetic interaction screens to identify synthetic lethal relationships

These strategies can illuminate how these two diabetes-associated genes functionally interact in cellular processes.

What considerations are important when targeting CDC123 for therapeutic development?

Researchers considering CDC123 as a therapeutic target should address:

• Target validation:

  • Confirm CDC123's role across multiple cancer models

  • Validate correlation between CDC123 expression and clinical outcomes

  • Determine therapeutic window based on differential expression in normal vs. cancer tissues

• Intervention strategies:

  • Direct CDC123 inhibition through small molecules or peptides

  • Indirect targeting via USP9X inhibition (e.g., WP1130/Degrasyn)

  • RNA interference approaches for expression knockdown

• Potential challenges:

  • Specificity concerns given CDC123's role in normal cell cycle regulation

  • Delivery to specific tissues (breast cancer, hepatocellular carcinoma)

  • Development of resistance mechanisms

• Combination approaches:

  • CDC123-targeted therapy with standard cancer treatments

  • Dual targeting of CDC123 and interacting partners (USP9X, CDKAL1)

  • Cell cycle-specific combination strategies

This multifaceted approach can guide rational drug development targeting the CDC123 pathway.

What are the unresolved questions regarding CDC123's molecular mechanisms?

Several key questions remain unexplored:

• The precise molecular mechanism by which CDC123 facilitates biogenesis of eukaryotic initiation factor 2 (eIF2)

• How CDC123's function in translation initiation relates to its role in cell cycle progression

• The specific transcriptional networks controlled by CDC123 during cell cycle progression

• How post-translational modifications beyond ubiquitination affect CDC123 function

• CDC123's potential roles in cellular processes beyond cell cycle regulation and translation

These knowledge gaps represent opportunities for researchers to make significant contributions to the field.

How can emerging technologies enhance CDC123 research?

Advanced methodologies can accelerate CDC123 research:

• CRISPR-based approaches:

  • Genome-wide CRISPR screens to identify synthetic lethal interactions with CDC123

  • CRISPRi/CRISPRa for precise transcriptional control

  • Base editing for studying specific CDC123 variants

• Single-cell technologies:

  • Single-cell RNA-seq to examine cell cycle-specific CDC123 functions

  • Single-cell proteomics to track CDC123 levels during cell cycle progression

  • Spatial transcriptomics to investigate tissue-specific expression patterns

• Structural biology:

  • Cryo-EM to resolve CDC123 protein structure and interaction interfaces

  • Hydrogen-deuterium exchange mass spectrometry for dynamics studies

  • Computational modeling for drug binding prediction

These cutting-edge approaches can provide unprecedented insights into CDC123 biology.