PRKAB2 is encoded by the PRKAB2 gene located on chromosome 1 (1q21.2) and spans approximately 17.7 kb . The protein comprises 272 amino acids (aa) with a molecular mass of 32.8 kDa . Key structural features include:
Non-catalytic regulatory subunit: Binds to AMPK’s catalytic α-subunit (PRKAA1/2) and γ-subunit (PRKAG1-3) .
His-tag fusion: Recombinant PRKAB2 produced in E. coli includes a 24-amino acid N-terminal His-tag for purification .
Tissue specificity: Highly expressed in skeletal muscle, with significant expression in liver and other metabolic tissues .
PRKAB2 is essential for AMPK’s activation in response to low ATP/AMP ratios, enabling cells to adapt to energy deficits. Its roles include:
AMPK activation: PRKAB2 stabilizes the AMPK complex, facilitating phosphorylation of downstream targets like acetyl-CoA carboxylase (ACC) and HMG-CoA reductase (HMGCR), thereby inhibiting fatty acid and cholesterol synthesis .
Autophagy and apoptosis: AMPK activation via PRKAB2 promotes autophagy (via ATG1/ULK1) and apoptosis (via inhibition of mTORC1) .
PRKAB2 has been implicated in cancer, metabolic disorders, and infectious diseases. Below are key studies:
A 2024 study in Cancers found low PRKAB2 expression correlates with poor outcomes in pediatric ACTs :
A 2025 study in Frontiers in Genetics identified PRKAB2 variants associated with HIV set-point viral load:
Genetic associations: Chromosome 1 variants (e.g., rs72999655, rs7525622) reduced PRKAB2 expression in monocytes, impacting immune signaling .
Functional impact: PRKAB2 loss-of-function altered cytokine pathways and pluripotency genes, potentially influencing HIV progression .
Type 2 diabetes: PRKAB2 variants near the 1q21.2 diabetes linkage peak in Pima Indians were studied, though no direct associations were found .
1q21.1 deletion syndrome: PRKAB2 loss-of-function is linked to impaired energy metabolism and DNA repair deficits .
PRKAB2 interacts with catalytic (α) and regulatory (γ) AMPK subunits to form the active trimer. Key interactions include:
PRKAG1/2/3: AMP/ATP-binding γ-subunits that stabilize AMPK’s response to energy stress .
STK11 (LKB1): Phosphorylates AMPK’s α-subunit, enhancing PRKAB2-mediated activation .
PRKAB2 modulation is explored in cancer therapy and metabolic diseases:
PRKAB2 is located on chromosome 1, upstream of CHD1L. Current research indicates that variants in this chromosomal region may influence the expression of both genes. When investigating PRKAB2 expression, researchers should consider:
The proximity of PRKAB2 to CHD1L, which suggests potential co-regulation of these genes in certain cell types
Cell-type specific expression patterns, as demonstrated by GTEx and ImmVar datasets
The presence of regulatory variants that may influence expression differently across cell types
Expression correlation analyses show that PRKAB2 and CHD1L have a strong positive correlation in whole blood (r = 0.7, p < 3.1 × 10^-110), no significant correlation in naïve CD4+ T cells (r = 0.17, p < 0.081), and a significant negative correlation in monocytes (r = −0.29, p < 0.002) . These findings highlight the importance of cell-type specificity when studying PRKAB2 regulation.
When designing experiments to study PRKAB2 function, researchers should consider multiple complementary approaches:
Cell line selection:
Primary human cells (monocytes, T cells) provide physiologically relevant contexts
Induced pluripotent stem cells (iPSCs) allow for genetic manipulation and differentiation
Loss-of-function approaches:
CRISPR-Cas9 knockout models, as demonstrated in recent iPSC studies
RNA interference for transient knockdown
Small molecule inhibitors of AMPK activity
Expression analysis methods:
RNA-sequencing for transcriptome-wide effects
qPCR for targeted expression analysis
Protein analysis via western blotting to confirm functional impacts
Recent research has utilized PRKAB2-/- iPSC models to investigate downstream effects of PRKAB2 loss, revealing significant changes in genes related to cytokine activity, growth factor signaling, and pluripotency pathways associated with HIV infection . When creating knockout models, researchers should be aware that different guide RNA efficiencies may result in varying degrees of knockdown, as demonstrated by the differences between clone 1 and clone 2 in recent studies .
A comprehensive approach to studying PRKAB2 expression across human tissues and cell types should include:
Database utilization:
GTEx database for tissue-specific expression data
Single-cell RNA-seq databases to understand cellular heterogeneity
ImmVar project data for immune cell expression patterns
Experimental validation:
Flow cytometry for protein-level confirmation in specific cell populations
Immunohistochemistry for spatial expression patterns in tissues
Cell sorting combined with qPCR or RNA-seq for purified cell populations
Statistical considerations:
Control for batch effects, sex, and technical variation
Use appropriate correlation measures (e.g., Pearson for normally distributed data)
Apply multiple testing correction for genome-wide analyses
When analyzing expression data, researchers should normalize appropriately using methods such as transcripts per million (TPM) for RNA-seq data or calculate residuals after controlling for non-genetic factors, as demonstrated in recent studies using GTEx and ImmVar datasets .
Recent genome-wide association studies (GWAS) have identified variants in the PRKAB2-CHD1L region associated with reduced HIV set-point viral load (spVL). When investigating the role of PRKAB2 genetic variants in HIV pathogenesis, researchers should consider:
Genetic analysis approaches:
Fine-mapping studies to identify causal variants from GWAS signals
PrediXcan models for imputing gene expression from genotype data
eQTL analysis to link variants to gene expression changes
Variant characterization:
Allele-specific expression assays to determine cis-regulatory effects
CRISPR-mediated genomic editing to validate variant effects
Reporter assays to test enhancer/promoter activity
Functional validation:
HIV infection assays in relevant cell types with variant-specific backgrounds
Co-expression analysis with known HIV restriction factors
Pathway analysis to identify downstream effects
Current data shows that individuals heterozygous for HIV spVL associated variants (rs72999655-A-G, rs7525622-G-A, and rs73004025-C-T) exhibit reduced PRKAB2 expression in monocytes and whole blood, suggesting a potential mechanism where lower PRKAB2 expression is associated with reduced HIV spVL . The table below summarizes the effects of these variants on PRKAB2 expression:
Variant | Cell Type | Effect on PRKAB2 Expression | Statistical Significance |
---|---|---|---|
rs59784663-A-G | Monocytes | Significant reduction | p < 0.036 |
rs59784663-A-G | Naïve CD4+ T cells | No significant effect | p < 0.56 |
rs72999655-A-G, rs7525622-G-A, rs73004025-C-T (combined) | Whole blood | Reduction in expression | Statistically significant |
The complex relationship between PRKAB2 and CHD1L requires careful experimental design:
Co-expression analysis:
Correlation studies across different cell types and conditions
Time-course experiments to capture dynamic relationships
Single-cell analysis to address cellular heterogeneity
Protein interaction studies:
Co-immunoprecipitation to detect physical interactions
Proximity ligation assays for in situ detection
Mass spectrometry to identify interaction partners
Mechanistic investigations:
ChIP-seq to identify shared or distinct binding sites
RNA-seq after PRKAB2 or CHD1L perturbation
Phosphoproteomics to identify AMPK-mediated effects on CHD1L
Research has shown that PRKAB2 loss-of-function can affect CHD1L expression, with significant downregulation observed in some knockout models . This suggests a potential regulatory relationship that may involve AMPK activation initiating DNA repair pathways involving CHD1L . When designing experiments, researchers should be aware that effects may be cell-type specific and dependent on the level of PRKAB2 knockdown achieved.
When investigating transcriptomic changes resulting from PRKAB2 modulation:
RNA-sequencing considerations:
Use multiple biological replicates (minimum 3-4 per condition)
Consider time-course designs to capture dynamic responses
Include appropriate controls (e.g., wild-type, empty vector)
Apply rigorous quality control and normalization
Analysis approaches:
Differential expression analysis with appropriate multiple testing correction
Pathway enrichment using tools like DAVID, GSEA, or Ingenuity
Network analysis to identify key regulatory hubs
Integration with phosphoproteomic data when possible
Validation strategies:
qPCR confirmation of key differentially expressed genes
Protein-level validation via western blotting or proteomics
Functional assays targeting identified pathways
Recent research comparing PRKAB2-/- iPSCs with wild-type cells identified 315 differentially expressed genes (170 downregulated, 145 upregulated) . Pathway analysis revealed significant enrichment for functions related to cytokine activity, growth factor binding, and pluripotency pathways . When conducting similar analyses, researchers should be aware that the functional AMPK complex regulates gene expression primarily through phosphorylation, which is not directly detectable through RNA-sequencing. Therefore, integration with protein-level data is crucial for a complete understanding.
AMPK functions as a heterotrimeric complex, requiring careful consideration when studying PRKAB2's role:
Complex assembly analysis:
Co-immunoprecipitation to assess interaction with alpha and gamma subunits
Blue native PAGE to preserve intact protein complexes
Size-exclusion chromatography to separate assembled complexes
Functional activity assessment:
Kinase activity assays using AMPK-specific substrates
Phospho-specific antibodies against known AMPK targets
Cellular assays measuring metabolic responses
Isoform-specific considerations:
Distinguish between AMPKβ1 and AMPKβ2 functions using isoform-specific approaches
Control for potential compensatory mechanisms when one isoform is depleted
Consider tissue-specific expression patterns of different isoforms
AMPK is comprised of an alpha subunit (PRKAA1/PRKAA2), beta subunit (PRKAB1/PRKAB2), and gamma subunit (PRKAG1/PRKAG2/PRKAG3) . When studying PRKAB2 specifically, researchers should be aware that AMPKβ1 and AMPKβ2 exhibit different transcriptome profiles , necessitating isoform-specific approaches.
Given AMPK's known role in inflammatory regulation, studies of PRKAB2 in this context should consider:
Stimulation protocols:
Use relevant pro-inflammatory stimuli (LPS, cytokines)
Include time-course designs to capture both early and late responses
Consider dose-response relationships to identify threshold effects
Readout selection:
Measure cytokine production via ELISA or multiplex assays
Assess activation of signaling pathways (NF-κB, MAPK, STAT)
Evaluate transcription factor binding via ChIP-seq
Cell model considerations:
Primary human macrophages or monocytes for physiological relevance
Matched PRKAB2-sufficient and -deficient cells
Consider tissue-specific macrophage phenotypes
AMPK has been shown to repress pro-inflammatory signaling and activate anti-inflammatory signaling in macrophages . Research has identified that PRKAB2 loss-of-function affects the expression of genes involved in cytokine activity, including TNFSF9, TGFB2, and others that interact with HIV proteins . When designing experiments, researchers should be aware that AMPK influences inflammatory pathways through both direct phosphorylation events and longer-term transcriptional effects.
When conducting genetic association studies focused on PRKAB2:
Study population selection:
Consider ancestry-specific effects and population structure
Include diverse populations to enhance generalizability
Account for demographic and clinical covariates
Variant selection and analysis:
Include both common and rare variants in the PRKAB2 region
Consider haplotype structure and linkage disequilibrium
Utilize imputation to increase coverage of variants
Functional validation approaches:
eQTL analysis to link variants to expression changes
Allele-specific reporter assays for regulatory variants
CRISPR-based approaches for variant validation
Recent studies utilized genotype data from 3,886 individuals of African ancestry from the International Collaboration for the Genomics of HIV (ICGH) . Predictive gene expression models trained on African American whole blood eQTLs were applied using PrediXcan to analyze the relationship between genetic variants and gene expression . When designing similar studies, researchers should be aware that regulatory variants can influence the expression of multiple genes which collectively contribute to complex phenotypes .
As the field evolves, several advanced technologies offer new opportunities:
Single-cell multi-omics:
Integrated single-cell RNA-seq, ATAC-seq, and proteomics
Spatial transcriptomics to map expression in tissue contexts
Single-cell proteomics for protein-level validation
Advanced genetic engineering:
Base editing for precise genetic modifications
CRISPR activation/inhibition for modulating expression
Inducible systems for temporal control of gene expression
Physiological models:
Organoid systems for tissue-specific contexts
Humanized mouse models for in vivo studies
Patient-derived iPSCs for personalized disease modeling
These technologies will enable more precise characterization of PRKAB2 function in specific cellular contexts and disease states, moving beyond correlation to establish causality in complex biological systems.
Integration across model systems presents significant challenges but offers comprehensive insights:
Cross-platform data integration:
Meta-analysis approaches for combining study results
Machine learning models to identify consistent patterns
Network-based approaches to map pathway conservation
Translation considerations:
Careful mapping of orthologous genes across species
Validation of key findings in human samples
Accounting for species-specific regulatory differences
Collaborative approaches:
Multi-disciplinary team science
Data sharing through public repositories
Standardized protocols to enhance reproducibility
Effective integration requires careful consideration of the strengths and limitations of each model system, with human data serving as the ultimate validation for findings from experimental models.
Protein Kinase, AMP-Activated, Beta 2 Non-Catalytic Subunit, also known as PRKAB2, is a regulatory subunit of the AMP-activated protein kinase (AMPK) complex. AMPK is a crucial energy-sensing enzyme that plays a significant role in maintaining cellular energy homeostasis. It is a heterotrimeric complex composed of an alpha catalytic subunit and non-catalytic beta and gamma subunits .
The PRKAB2 subunit is integral to the AMPK complex’s function. It acts as a scaffold, facilitating the assembly of the alpha and gamma subunits. This subunit is involved in the regulation of AMPK activity through its myristoylation and phosphorylation, which affect the enzyme’s activity and cellular localization .
AMPK is activated in response to metabolic stresses that deplete cellular ATP levels, such as exercise, hypoxia, and glucose deprivation. Upon activation, AMPK phosphorylates and inactivates key enzymes involved in anabolic processes, thereby conserving ATP. It also promotes catabolic processes that generate ATP, thus restoring energy balance within the cell .
The AMPK complex, including the PRKAB2 subunit, is essential for cellular energy regulation. It inhibits energy-consuming processes like protein, carbohydrate, and lipid biosynthesis, while promoting energy-producing pathways. This regulation is vital for cellular adaptation to metabolic stress and maintaining overall energy homeostasis .
Mutations or dysregulation of the PRKAB2 subunit and the AMPK complex have been associated with various metabolic disorders and diseases. For instance, alterations in AMPK activity are linked to conditions such as obesity, type 2 diabetes, and cancer. Understanding the role of PRKAB2 in these processes can provide insights into potential therapeutic targets for these diseases .