PRKAB2

PRKAB2 encodes the β2 regulatory subunit of the heterotrimeric AMP-activated protein kinase (AMPK) complex, and its dosage directly governs cellular AMPK activity: reduced PRKAB2 protein, as seen in 1q21.1 deletion carrier cells, specifically attenuates AMPK function (PMID:21824431). Through this regulatory role, PRKAB2 is indispensable for mesoderm specification and cardiomyocyte differentiation in human iPSCs, with knockout abolishing cardiac lineage commitment (PMID:33454005). In renal cell carcinoma, PRKAB2 acts as a tumor suppressor that inhibits mitophagy by two convergent routes — enhancing LRPPRC–PRKN binding to competitively displace PRKN from PINK1, and driving AMPK-mediated suppression of SREBF1-dependent transcription of CRLS1 to limit cardiolipin synthesis — and its overexpression restores sunitinib sensitivity in resistant cells (PMID:41612594). PRKAB2 is also the β-subunit target through which methyl-β-cyclodextrin activates AMPK to restore autophagy flux in NPC1-deficient cells (PMID:28613987), and it is a direct target of miR-29b whose downregulation promotes apoptosis and inflammation in high-glucose-treated podocytes (PMID:38204237).

1. 2011 Medium

   Established that PRKAB2 gene dosage directly sets AMPK activity, linking copy-number variation to a quantitative biochemical readout.

   Evidence Western blot and AMPK activity assays in lymphoblast lines from 1q21.1 deletion/duplication carriers

   PMID:21824431

   Open questions at the time

   • Does not resolve which downstream AMPK substrates are affected
   • Single patient-derived cell system, no rescue by re-expression
2. 2016 Low

   Placed PRKAB2 as the β2 isoform within the heterotrimeric AMPK complex and raised the possibility of isoform-specific localization and context-dependent oncogenic roles.

   Evidence Review/synthesis of isoform genetics and tumour amplification data (no primary experiment)

   PMID:26934201

   Open questions at the time

   • No primary experiment on PRKAB2 in this work
   • Isoform-specific localization not directly demonstrated
   • Oncogenic versus tumour-suppressor role unresolved
3. 2017 Medium

   Identified the AMPK β-subunit, including PRKAB2, as the direct molecular target through which methyl-β-cyclodextrin activates AMPK to enhance autophagy flux.

   Evidence siRNA knockdown of PRKAB1/PRKAB2 with AMPK activity assays and cholesterol storage measurements in NPC1-deficient cells

   PMID:28613987

   Open questions at the time

   • Direct binding site on the β-subunit not structurally mapped
   • Redundancy between PRKAB1 and PRKAB2 not fully separated
4. 2020 Medium

   Demonstrated that PRKAB2 is required at the mesoderm specification stage for cardiac lineage commitment, defining a developmental function beyond metabolic sensing.

   Evidence CRISPR/Cas9 knockout in hiPSCs with RNA-Seq and histochemical staining for cardiac markers

   PMID:33454005

   Open questions at the time

   • Mechanism linking AMPK β2 loss to mesoderm gene programs not defined
   • Single lab, single cellular model
5. 2024 Medium

   Positioned PRKAB2 downstream of miR-29b in podocyte injury, showing its repression mediates apoptosis and inflammation in a diabetic nephropathy context.

   Evidence Luciferase reporter, Western blot, siRNA knockdown with apoptosis (flow cytometry) and cytokine (ELISA) readouts in high-glucose podocytes

   PMID:38204237

   Open questions at the time

   • AMPK-dependence of the protective effect not directly tested
   • In vitro only, single lab
6. 2026 High

   Defined PRKAB2 as a tumor suppressor in RCC that inhibits mitophagy through dual mechanisms and modulates drug sensitivity, providing the most detailed mechanistic model to date.

   Evidence In vivo genome-wide CRISPR screen, reciprocal Co-IP, ChIP, overexpression/knockdown, and tumor growth assays in vitro and in vivo

   PMID:41612594

   Open questions at the time

   • Whether these mitophagy mechanisms generalize beyond RCC is untested
   • Structural basis of LRPPRC–PRKN modulation not resolved

• How PRKAB2-specific (versus PRKAB1) AMPK complexes are targeted to distinct substrates and localizations across these diverse tissue contexts remains unresolved.
• No structural model of PRKAB2 within the AMPK heterotrimer in the corpus
• Isoform-selective substrate specificity not directly defined
• Reconciliation of tumor-suppressor versus oncogenic roles across tissues unestablished