Project description:Neatly every proteomic protocol has a Cysteine reduction and alkylation step in it preceding the trypsin digestion. It needs to be done in order to remove the s-s bonds and prevent proteins from folding, thus, provide better access for trypsin. Among various reagents used for alkylation, iodoacetamide (IAM) seems to be the most common. Although, it has been shown that IAM can cause some undesired side reactions [Chernobrovkin et al., 2015; Muller et al., 2017]. In this work, we have compared the effect of four alkylating agents: iodoacetamide (IAM), 4-vinylpyridine (4-VP), chloroacetamide (CAM) and S-Methyl methanethiosulfonate (MMTS). In addition, we tried to check whether post-treatment with DTT (p-red) is reasonable in the case of irreversible alkylation.
Project description:Neatly every proteomic protocol has a Cysteine reduction and alkylation step in it preceding the trypsin digestion. It needs to be done in order to remove the s-s bonds and prevent proteins from folding, thus, provide better access for trypsin. Among various reagents used for alkylation, iodoacetamide (IAM) seems to be the most common. Although, it has been shown that IAM can cause some undesired side reactions [Chernobrovkin et al., 2015; Muller et al., 2017]. In this work, we have compared the effect of four alkylating agents: iodoacetamide (IAM), 4-vinylpyridine (4-VP), chloroacetamide (CAM) and S-Methyl methanethiosulfonate (MMTS). In addition, we tried to check whether post-treatment with DTT (p-red) is reasonable in the case of irreversible alkylation.
Project description:Magnaporthe oryzae snodprot1 homologous protein (MSP1) has been shown to act as a pathogen-associated molecular pattern (PAMPs) and trigger PAMP-triggered immunity (PTI) response involving programmed cell death and expression of various defense-related genes in rice. The involvement of several post-translational modifications (PTMs) in the regulation of plant immune response, especially PTI, during pathogen infection is well established, however, the information on the regulatory roles of these PTMs in response to MSP1-induced signaling in rice is currently elusive. Here, we report the phosphoproteome, ubiquitinome, and acetylproteome to investigate the MSP1-induced PTMs alterations in MSP1 overexpressed rice. Our analysis identified a total of 4,666 PTM modified sites in rice leaves including 4,292 phosphosites, 189 ubiquitin sites, and 185 acetylation sites. Among these, PTM status of 437 phosphorylated, 53 ubiquitinated, and 68 acetylated peptides were significantly changed by MSP1. Functional annotation of MSP1 modulated peptides by MapMan analysis revealed that these were majorly associated with cellular immune responses such as signaling, transcription factors, DNA and RNA regulation, and protein metabolism, among others. Taken together, this study uncovers the MSP1-induced PTMs changes in rice proteins and identified several novel components of rice-MSP1 interaction.
Project description:LC-MS/MS analysis of O-GlcNAcylated ChREBP proteins, which were overexpressed in HEK293T cells and purified via affinity purification using Ni-NTA agarose
Project description:Many disease-causing missense mutations affect intrinsically disordered regions (IDRs) of proteins. Since these mutations do not affect protein structure, the molecular mechanism of their pathogenicity is enigmatic. Here, we employ a peptide-based proteomic screen to investigate the impact of mutations in IDRs on protein-protein interactions. We find that mutations in disordered cytosolic regions of three transmembrane proteins (GLUT1, ITPR1 and CACNA1H) lead to an increased binding of clathrin. In all three cases, the mutation creates a dileucine motif known to mediate clathrin-dependent trafficking. Follow-up experiments on full length GLUT1 (SLC2A1), the glucose transporter causative of GLUT1 deficiency syndrome, revealed that the mutated protein mislocalizes to intracellular compartments in a model cell line and in patient-derived induced pluripotent stem cells. Mutant GLUT1 interacts with adaptor proteins (APs) in vitro, and knocking-down AP-2 reverts the cellular mislocalization. A systematic analysis of other known disease-causing variants revealed a significant and specific overrepresentation of gained dileucine motifs in structurally disordered cytosolic domains of transmembrane proteins. Thus, several mutations in disordered regions appear to cause “dileucineopathies”.
Project description:We collected samples of Pistil, Plain Valve, Plain lip and Plain calyx from the same period and quenched them in liquid nitrogen. Two biological replications were performed in each sample. TMT labeled quantitative proteomics was used to analyze different proteins in different tissues. GO and KEGG were used to analyze the differentially expressed proteins in different tissues, and the key proteins in the important pathway were found
Project description:Heterotrimeric guanine nucleotide-binding (G) proteins are composed of Gα, Gβ, and Gγ subunits, and function as molecular switches in signal transduction. In Arabidopsis thaliana there are one canonical Gα (GPA1), three extra-large Gα (XLG1, XLG2 and XLG3), one Gβ (AGB1) and three Gγ (AGG1, AGG2 and AGG3) subunits. To elucidate AGB1 molecular signaling, we performed immunoprecipitation using plasma membrane enriched proteins followed by mass spectrometry to identify the protein interactors of AGB1. After eliminating proteins present in the control immunoprecipitation, commonly identified contaminants, and organellar proteins, a total of 103 candidate AGB1-associated proteins were confidently identified. We identified all of the G protein subunits except XLG1, receptor-like kinases (RLKs), Ca2+ signaling related proteins and 14-3-3-like proteins, all of which may couple with or modulate G protein signaling.
Project description:Ligand-stimulated epidermal growth factor receptor (EGFR) signaling plays fundamental roles in normal cell physiology, such as cell growth, cell proliferation, and cell survival. Deregulation of EGFR signaling contributes to the development and progression of diseases including cancer. Despite its essential role in biology, the mechanisms by which EGFR signaling is regulated in cells are still poorly understood. Here, we demonstrate that O-linked N-acetyl-glucosamine (O-GlcNAc) modification serves as an important regulator of EGFR intracellular trafficking and degradation. Mechanistically, O-GlcNAcylation of hepatocyte growth factor regulated tyrosine kinase substrate (HGS), a key protein in EGFR intraluminal sorting pathway, inhibits HGS interaction with signal-transducing adaptor molecule (STAM), thereby impairing the formation of endosomal sorting complex required for transport-0 (ESCRT-0). Moreover, O-GlcNAcylation increases HGS ubiquitination and decreases its protein stability in cells. Consequently, HGS O-GlcNAcylation inhibits EGFR intraluminal sorting and lysosomal degradation, leading to the accumulation of EGFR and prolonged EGFR signaling in cells.
Project description:The client-specificity of TMX3, TMX4 and TMX5 in cellula, was assessed by expressing mutant forms of the enzymes, where the last cysteine residue of the TMX’s CXXC catalytic sites has been mutated to alanine, which stabilizes the mixed disulfide that oxidoreductases establish with clients. Clients remain disulfide-bonded to the oxidoreductase and are identified upon co-immunoprecipitation and mass spectrometry analyses.