Combined inhibition of KRAS and mTORC1 kinase is synergistic in non-small cell lung cancer.

Current KRAS (OFF) inhibitors that target inactive GDP-bound KRAS cause responses in less than half of patients and these responses are not durable. A class of RAS (ON) inhibitors that targets active GTP-bound KRAS blocks ERK signaling more potently than the inactive-state inhibitors. Sensitivity to either class of agents is strongly correlated with inhibition of mTORC1 activity.

CryoEM structural exploration of catalytically active enzyme pyruvate carboxylase.

Pyruvate carboxylase (PC) is a tetrameric enzyme that contains two active sites per subunit that catalyze two consecutive reactions. A mobile domain with an attached prosthetic biotin links both reactions, an initial biotin carboxylation and the subsequent carboxyl transfer to pyruvate substrate to produce oxaloacetate. Reaction sites are at long distance, and there are several co-factors that play as allosteric regulators.

A Rationally Designed c-di-AMP Förster Resonance Energy Transfer Biosensor To Monitor Nucleotide Dynamics.

3'3'-Cyclic di-AMP (c-di-AMP) is an important nucleotide second messenger found throughout the bacterial domain of life. c-di-AMP is essential in many bacteria and regulates a diverse array of effector proteins controlling pathogenesis, cell wall homeostasis, osmoregulation, and central metabolism. Despite the ubiquity and importance of c-di-AMP, methods to detect this signaling molecule are limited, particularly at single-cell resolution.

Structural and functional studies of pyruvate carboxylase regulation by cyclic di-AMP in lactic acid bacteria.

Cyclic di-3',5'-adenosine monophosphate (c-di-AMP) is a broadly conserved bacterial second messenger that has been implicated in a wide range of cellular processes. Our earlier studies showed that c-di-AMP regulates central metabolism in by inhibiting its pyruvate carboxylase (LmPC), a biotin-dependent enzyme with biotin carboxylase (BC) and carboxyltransferase (CT) activities. We report here structural, biochemical, and functional studies on the inhibition of PC (LlPC) by c-di-AMP.

c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation.

Cyclic diadenosine monophosphate (c-di-AMP) is a conserved nucleotide second messenger critical for bacterial growth and resistance to cell wall-active antibiotics. In Listeria monocytogenes, the sole diadenylate cyclase, DacA, is essential in rich, but not synthetic media and ΔdacA mutants are highly sensitive to the β-lactam antibiotic cefuroxime. In this study, loss of function mutations in the oligopeptide importer (oppABCDF) and glycine betaine importer (gbuABC) allowed ΔdacA mutants to grow in rich medium.

A distinct holoenzyme organization for two-subunit pyruvate carboxylase.

Pyruvate carboxylase (PC) has important roles in metabolism and is crucial for virulence for some pathogenic bacteria. PC contains biotin carboxylase (BC), carboxyltransferase (CT) and biotin carboxyl carrier protein (BCCP) components. It is a single-chain enzyme in eukaryotes and most bacteria, and functions as a 500 kD homo-tetramer.

Cyclic di-AMP targets the cystathionine beta-synthase domain of the osmolyte transporter OpuC.

Cellular turgor is of fundamental importance to bacterial growth and survival. Changes in external osmolarity as a consequence of fluctuating environmental conditions and colonization of diverse environments can significantly impact cytoplasmic water content, resulting in cellular lysis or plasmolysis. To ensure maintenance of appropriate cellular turgor, bacteria import ions and small organic osmolytes, deemed compatible solutes, to equilibrate cytoplasmic osmolarity with the extracellular environment.

Molecular basis for the recognition of cyclic-di-AMP by PstA, a PII-like signal transduction protein.

Cyclic-di-AMP (c-di-AMP) is a broadly conserved bacterial second messenger that is of importance in bacterial physiology. The molecular receptors mediating the cellular responses to the c-di-AMP signal are just beginning to be discovered. PstA is a previously uncharacterized PII -like protein which has been identified as a c-di-AMP receptor.

The cyclic dinucleotide c-di-AMP is an allosteric regulator of metabolic enzyme function.

Cyclic di-adenosine monophosphate (c-di-AMP) is a broadly conserved second messenger required for bacterial growth and infection. However, the molecular mechanisms of c-di-AMP signaling are still poorly understood. Using a chemical proteomics screen for c-di-AMP-interacting proteins in the pathogen Listeria monocytogenes, we identified several broadly conserved protein receptors, including the central metabolic enzyme pyruvate carboxylase (LmPC).

Characterizing the importance of the biotin carboxylase domain dimer for Staphylococcus aureus pyruvate carboxylase catalysis.

Biotin carboxylase (BC) is a conserved component among biotin-dependent carboxylases and catalyzes the MgATP-dependent carboxylation of biotin, using bicarbonate as the CO₂ donor. Studies with Escherichia coli BC have suggested long-range communication between the two active sites of a dimer, although its mechanism is not well understood. In addition, mutations in the dimer interface can produce stable monomers that are still catalytically active.

Folding of a single-chain, information-rich polypeptoid sequence into a highly ordered nanosheet.

The design and synthesis of protein-like polymers is a fundamental challenge in materials science. A means to achieve this goal is to create synthetic polymers of defined sequence where all relevant folding information is incorporated into a single polymer strand. We present here the aqueous self-assembly of peptoid polymers (N-substituted glycines) into ultrathin, two-dimensional highly ordered nanosheets, where all folding information is encoded into a single chain.

Free-floating ultrathin two-dimensional crystals from sequence-specific peptoid polymers.

The design and synthesis of protein-like polymers is a fundamental challenge in materials science. A biomimetic approach is to explore the impact of monomer sequence on non-natural polymer structure and function. We present the aqueous self-assembly of two peptoid polymers into extremely thin two-dimensional (2D) crystalline sheets directed by periodic amphiphilicity, electrostatic recognition and aromatic interactions.