Dataset Information

Light-Triggered Carotenogenesis in Myxococcus xanthus: New Paradigms in Photosensory Signaling, Transduction and Gene Regulation.

ABSTRACT: Myxobacteria are Gram-negative δ-proteobacteria found predominantly in terrestrial habitats and often brightly colored due to the biosynthesis of carotenoids. Carotenoids are lipophilic isoprenoid pigments that protect cells from damage and death by quenching highly reactive and toxic oxidative species, like singlet oxygen, generated upon growth under light. The model myxobacterium Myxococcus xanthus turns from yellow in the dark to red upon exposure to light because of the photoinduction of carotenoid biosynthesis. How light is sensed and transduced to bring about regulated carotenogenesis in order to combat photooxidative stress has been extensively investigated in M. xanthus using genetic, biochemical and high-resolution structural methods. These studies have unearthed new paradigms in bacterial light sensing, signal transduction and gene regulation, and have led to the discovery of prototypical members of widely distributed protein families with novel functions. Major advances have been made over the last decade in elucidating the molecular mechanisms underlying the light-dependent signaling and regulation of the transcriptional response leading to carotenogenesis in M. xanthus. This review aims to provide an up-to-date overview of these findings and their significance.

SUBMITTER: Padmanabhan S

PROVIDER: S-EPMC8156234 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

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Publications

Light-Triggered Carotenogenesis in <i>Myxococcus xanthus</i>: New Paradigms in Photosensory Signaling, Transduction and Gene Regulation.

Padmanabhan S S Monera-Girona Antonio J AJ Pérez-Castaño Ricardo R Bastida-Martínez Eva E Pajares-Martínez Elena E Bernal-Bernal Diego D Galbis-Martínez María Luisa ML Polanco María Carmen MC Iniesta Antonio A AA Fontes Marta M Elías-Arnanz Montserrat M

Microorganisms 20210515 5

Myxobacteria are Gram-negative δ-proteobacteria found predominantly in terrestrial habitats and often brightly colored due to the biosynthesis of carotenoids. Carotenoids are lipophilic isoprenoid pigments that protect cells from damage and death by quenching highly reactive and toxic oxidative species, like singlet oxygen, generated upon growth under light. The model myxobacterium <i>Myxococcus xanthus</i> turns from yellow in the dark to red upon exposure to light because of the photoinduction ...[more]

PMID: 34063365

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Project description:UnlabelledNADP(+) is a vital cofactor involved in a wide variety of activities, such as redox potential and cell death. Here, we show that NADP(+) negatively regulates an acetyltransferase from Myxococcus xanthus, Mxan_3215 (MxKat), at physiologic concentrations. MxKat possesses an NAD(P)-binding domain fused to the Gcn5-type N-acetyltransferase (GNAT) domain. We used isothermal titration calorimetry (ITC) and a coupled enzyme assay to show that NADP(+) bound to MxKat and that the binding had strong effects on enzyme activity. The Gly11 residue of MxKat was confirmed to play an important role in NADP(+) binding using site-directed mutagenesis and circular dichroism spectrometry. In addition, using mass spectrometry, site-directed mutagenesis, and a coupling enzymatic assay, we demonstrated that MxKat acetylates acetyl coenzyme A (acetyl-CoA) synthetase (Mxan_2570) at Lys622 in response to changes in NADP(+) concentration. Collectively, our results uncovered a mechanism of protein acetyltransferase regulation by the coenzyme NADP(+) at physiological concentrations, suggesting a novel signaling pathway for the regulation of cellular protein acetylation.ImportanceMicroorganisms have developed various protein posttranslational modifications (PTMs), which enable cells to respond quickly to changes in the intracellular and extracellular milieus. This work provides the first biochemical characterization of a protein acetyltransferase (MxKat) that contains a fusion between a GNAT domain and NADP(+)-binding domain with Rossmann folds, and it demonstrates a novel signaling pathway for regulating cellular protein acetylation in M. xanthus. We found that NADP(+) specifically binds to the Rossmann fold of MxKat and negatively regulates its acetyltransferase activity. This finding provides novel insight for connecting cellular metabolic status (NADP(+) metabolism) with levels of protein acetylation, and it extends our understanding of the regulatory mechanisms underlying PTMs.

Dataset Information

Light-Triggered Carotenogenesis in Myxococcus xanthus: New Paradigms in Photosensory Signaling, Transduction and Gene Regulation.

Publications

Light-Triggered Carotenogenesis in <i>Myxococcus xanthus</i>: New Paradigms in Photosensory Signaling, Transduction and Gene Regulation.

Similar Datasets

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