Dataset Information

Akt3 is a privileged first responder in isozyme-specific electrophile response.

ABSTRACT: Isozyme-specific post-translational regulation fine tunes signaling events. However, redundancy in sequence or activity renders links between isozyme-specific modifications and downstream functions uncertain. Methods to study this phenomenon are underdeveloped. Here we use a redox-targeting screen to reveal that Akt3 is a first-responding isozyme sensing native electrophilic lipids. Electrophile modification of Akt3 modulated downstream pathway responses in cells and Danio rerio (zebrafish) and markedly differed from Akt2-specific oxidative regulation. Digest MS sequencing identified Akt3 C119 as the privileged cysteine that senses 4-hydroxynonenal. A C119S Akt3 mutant was hypomorphic for all downstream phenotypes shown by wild-type Akt3. This study documents isozyme-specific and chemical redox signal-personalized physiological responses.

SUBMITTER: Long MJ

PROVIDER: S-EPMC5586141 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Akt3 is a privileged first responder in isozyme-specific electrophile response.

Long Marcus J C MJ Parvez Saba S Zhao Yi Y Surya Sanjna L SL Wang Yiran Y Zhang Sheng S Aye Yimon Y

Nature chemical biology 20170123 3

Isozyme-specific post-translational regulation fine tunes signaling events. However, redundancy in sequence or activity renders links between isozyme-specific modifications and downstream functions uncertain. Methods to study this phenomenon are underdeveloped. Here we use a redox-targeting screen to reveal that Akt3 is a first-responding isozyme sensing native electrophilic lipids. Electrophile modification of Akt3 modulated downstream pathway responses in cells and Danio rerio (zebrafish) and ...[more]

PMID: 28114274

Similar Datasets

Project description:Vascular smooth muscle cell (VSMC) dysregulation is a hallmark of vascular disease, including atherosclerosis. In particular, the majority of cells within atherosclerotic lesions are generated from pre-existing VSMCs and a clonal nature has been documented for VSMC-derived cells in multiple disease models. However, the mechanisms underlying the generation of oligoclonal lesions and the phenotype of proliferating VSMCs are unknown.Here we analyse clonal dynamics in multi-color lineage-traced animals over time after vessel injury to understand the cellular mechanisms underlying clonal VSMC expansion in disease.We demonstrate that VSMC proliferation is initiated in a small fraction of VSMCs that initially expand clonally in the medial layer and then migrate to form the oligoclonal neointima. Selective activation of VSMC proliferation also occurs in vitro, suggesting that this is a cell-autonomous feature. Mapping of VSMC trajectories using single-cell RNA-sequencing reveals a continuum of cellular states after injury and suggests that VSMC proliferation initiates in cells that have downregulated the contractile phenotype and show evidence of pronounced phenotypic switching. We show that proliferation is associated with induced expression of stem cell antigen 1 (SCA1) and the expression signature previously identified in SCA1+ VSMCs in healthy arteries. A remarkably increased proliferation of SCA1+ VSMCs, directly validated in functional assays, indicates that SCA1+ VSMCs act as "first responders" in vascular injury. Early atherosclerotic lesions also had clonal VSMC contribution and we show that the proliferation-associated injury response is conserved in plaque VSMCs, extending these findings to atherosclerosis. Finally, we identify VSMCs in healthy human arteries that correspond to the SCA1+ state in mouse VSMCs and show that genes identified as differentially expressed in this human VSMC subpopulation are enriched for genes showing genetic association with cardiovascular disease. We show that cell-intrinsic, selective VSMC activation drives clonal proliferation after injury and in atherosclerosis. Our study suggests that healthy mouse and human arteries contain VSMCs characterised by expression of disease-associated genes that are predisposed for proliferation. Targeting such "first responder" cells in patients undergoing vascular surgery could effectively prevent injury-associated VSMC activation and neoatherosclerosis.

Project description:The last step of cysteine biosynthesis in bacteria and plants is catalyzed by O-acetylserine sulfhydrylase. In bacteria, two isozymes, O-acetylserine sulfhydrylase-A and O-acetylserine sulfhydrylase-B, have been identified that share similar binding sites, although the respective specific functions are still debated. O-acetylserine sulfhydrylase plays a key role in the adaptation of bacteria to the host environment, in the defense mechanisms to oxidative stress and in antibiotic resistance. Because mammals synthesize cysteine from methionine and lack O-acetylserine sulfhydrylase, the enzyme is a potential target for antimicrobials. With this aim, we first identified potential inhibitors of the two isozymes via a ligand- and structure-based in silico screening of a subset of the ZINC library using FLAP. The binding affinities of the most promising candidates were measured in vitro on purified O-acetylserine sulfhydrylase-A and O-acetylserine sulfhydrylase-B from Salmonella typhimurium by a direct method that exploits the change in the cofactor fluorescence. Two molecules were identified with dissociation constants of 3.7 and 33 µM for O-acetylserine sulfhydrylase-A and O-acetylserine sulfhydrylase-B, respectively. Because GRID analysis of the two isoenzymes indicates the presence of a few common pharmacophoric features, cross binding titrations were carried out. It was found that the best binder for O-acetylserine sulfhydrylase-B exhibits a dissociation constant of 29 µM for O-acetylserine sulfhydrylase-A, thus displaying a limited selectivity, whereas the best binder for O-acetylserine sulfhydrylase-A exhibits a dissociation constant of 50 µM for O-acetylserine sulfhydrylase-B and is thus 8-fold selective towards the former isozyme. Therefore, isoform-specific and isoform-independent ligands allow to either selectively target the isozyme that predominantly supports bacteria during infection and long-term survival or to completely block bacterial cysteine biosynthesis.

Dataset Information

Akt3 is a privileged first responder in isozyme-specific electrophile response.

Publications

Akt3 is a privileged first responder in isozyme-specific electrophile response.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets