Fine-tuning AMPK in physiology and disease using point-mutant mouse models.

AMP-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that monitors the cellular energy status to adapt it to the fluctuating nutritional and environmental conditions in an organism. AMPK plays an integral part in a wide array of physiological processes, such as cell growth, autophagy and mitochondrial function, and is implicated in diverse diseases, including cancer, metabolic disorders, cardiovascular diseases and neurodegenerative diseases. AMPK orchestrates many different physiological outcomes by phosphorylating a broad range of downstream substrates. However, the importance of AMPK-mediated regulation of these substrates in vivo remains an ongoing area of investigation to better understand its precise role in cellular and metabolic homeostasis. Here, we provide a comprehensive overview of our understanding of the kinase function of AMPK in vivo, as uncovered from mouse models that harbor phosphorylation mutations in AMPK substrates. We discuss some of the inherent limitations of these mouse models, highlight the broader implications of these studies for understanding human health and disease, and explore the valuable insights gained that could inform future therapeutic strategies for the treatment of metabolic and non-metabolic disorders.

Improved Rigidin-Inspired Antiproliferative Agents with Modifications on the 7-Deazahypoxanthine C7/C8 Ring Systems.

To improve their aqueous solubility characteristics, water-solubilizing groups were added to some antiproliferative, rigidin-inspired 7-deazahypoxanthine frameworks after molecular modeling seemed to indicate that structural modifications on the C7 and/or C8 phenyl groups would be beneficial. To this end, two sets of 7-deazahypoxanthines were synthesized by way of a multicomponent reaction approach. It was subsequently determined that their antiproliferative activity against HeLa cells was retained for those derivatives with a glycol ether at the 4'-position of the C8 aryl ring system, while also significantly improving their solubility behavior. The best of these compounds were the equipotent 6-[4-(2-ethoxyethoxy)benzoyl]-2-(pent-4-yn-1-yl)-5-phenyl-1,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one 33 and 6-[4-(2-ethoxyethoxy)benzoyl]-5-(3-fluorophenyl)-2-(pent-4-yn-1-yl)-1,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one 59. Similarly to the parent 1, the new derivatives were also potent inhibitors of tubulin assembly. In treated HeLa cells, live cell confocal microscopy demonstrated their impact on microtubulin dynamics and spindle morphology, which is the upstream trigger of mitotic delay and cell death.

Structural and Functional Analysis of Pullulanase Type 1 (PulA) from Geobacillus thermopakistaniensis.

Pullulanase type I (PulA) is a debranching enzyme that specifically cleaves α-1,6-glycosidic linkages in pullulan. Pullulan has not only diverse applications in food industry but also has immune-stimulatory effects on B and T cells, and found to enhance the production of various anti-inflammatory cytokines in human. Moreover, pullulan has been suggested as a possible anti-cancer drug delivery agent without adjuvant due to its unique structure. The process of pullulan degradation is unresolved due to imprecise pullulanase structural characteristics. Therefore, the present study aimed to understand the structural and functional characteristics of pullulanase enzyme from Geobacillus thermopakistaniensis MAS1 strain using various computational approaches. The physio-chemical topographies and secondary structure of GT_PulA were explored using ProPram, InterPro and SMART. Various tools like I-TASSER, ModRefiner, RAMPAGE, PROCHECK and MOE 2009.10 were used to construct and verify the 3D structural model. The structural elucidation confirmed the significant domains, i.e., CBM48, CBM2, and TIM barrel having catalytically active residues, and conserved region YNGWDP. CBM2 domain along with TIM barrel has a capacity to bind different ligands and proved favorable for multiple substrate catalyses. These structural properties can have a potential effect on enhancing enzymatic activity of GT_PulA enzyme.