Project description:Na+/H+ exchanger 1 (NHE1; SLC9A1) is a transport protein responsible for pH regulation in various types of cells. In cardiac myocytes, NHE1 generates the largest transmembrane acid-extrusion flux and is therefore the most significant controller of the intracellular acid/base milieu. The protein itself is regulated by various enzymes, including kinases. A number of critically important sites have been identified, coupling NHE1 to signalling cascades such as cAMP. NHE1 activity is very sensitive to oxygen tension, thus linking metabolism with pH. However, the sites implicated in this effect are not known. This study identified novel phosphorylation sites on NHE1. The state of these residues regulates NHE1 activity, hence pH and a myriad of pH sensitive downstream processes. Dysregulated NHE1 activity has been shown in diseases of the heart. Identification of novel regulatory sites can help demarcate the mechanisms of disease and suggest possible interventions to correct NHE1 activity.
Project description:Purpose: Delonix regia or Gulmohor commonly grows here and there in Indian villages as well as it is used for megacity beautification and environmental management due to its evergreen nature and vibrant flower colour. However, an increasing incidence of seasonal pollinosis was observed among the inhabitants living in close vicinity to this tree suggesting a possible link between the airborne pollen load and the concomitant respiratory hazards. This prompted us to investigate the allergens in the pollen of this dominant avenue tree. Methodology: Allergenicity of D. regia pollen grains was first checked by Skin Prick Test (SPT) and further confirmed by in vitro tests, such as, ELISA, Dot Blot and histamine release assay. The total proteome profiling was done by 2D PAGE and it was confronted with the pooled sera of 10 patients. The IgE reactive proteins were identified by MALDI TOF/TOF in Autoflex speed (Bruker,Germany). The raw spectra were searched against NCBInr database using MASCOT search engine. Result: Delonix regia, pollen grains have been found in considerable amount in the air during its flowering season (May to July). Approximately 31% of atopic individuals were found allergic to D. regia, pollen with elevated level of specific IgE and histamine in the serum. Total 8 IgE reactive proteins have been identified by homology driven proteomics. These proteins are ATP synthase beta subunit (spot no 5), Actin (spot no 6), Hypothetical actin like protein (spot no 7), Recombinant S-adenosylmethionine synthase 2 (spot no 9), UDP-arabinopyranose mutase (spot no 13), Luminal-binding 5 (spot no 2), ELF3-like protein (spot no 8) and hypothetical protein OsJ_04810 (spot no 11). Among these eight identified allergenic proteins, five were previously reported as allergen from different sources whereas the rest three have been reported for the first time as novel allergens. Conclusion: Novelty of this study was to identify 8 allergens from D.regia for the first time using immune-biochemical and proteomic techniques. Further studies will open up new avenues in component resolved diagnosis of pollen allergy.
Project description:Shotgun proteomics focusing on the membrane proteomes, of four Synechococcus spp. strains namely CC9311 (clade I), CC9605 (Clade II), WH8102 (clade III) and CC9902 (clade IV) were conducted to gain insight into the amount of resources these unicellular organisms invest into adaptation strategies.
Project description:To characterize the nature of the cytochrome c1 (CYC1) processivity defect in native CIII2 assemblies we identified CYC1 peptides using mass spectrometry analysis of blue native (BN)-PAGE. Gel slices ranging from ~600-900kDa and containing CIII2 assemblies were excised from U2OS control cells, U2OS OCIAD1 knockdown cells, and U2OS OCIAD1 knockdown cells rescued with wildtype OCIAD1. Gel slices were then digested and analyzed by mass spectrometry.
Project description:O-GlcNAc glycosylation is a prevalent protein post-translational modification (PTM) that occurs intracellularly. Previous investigations have demonstrated that O-GlcNAcylation crosstalks with phosphorylation and ubiquitination, but it is unclear whether it interplays with other PTMs. Here we studied its relationship with ADP-ribosylation, which involves decorating target proteins with the ADP-ribose moiety. We discovered that one ADP-ribosylation “eraser”- ADP-ribose glycohydrolase (PARG)- is O-GlcNAcylated at Ser26. O-GlcNAcylation of PARG is essential to maintain its nuclear localization and chromatin association. In hepatocellular carcinoma (HCC) cells, PARG O-GlcNAcylation enhances DNA damage-binding protein 1 (DDB1) poly(ADP-ribosyl)ation (PARylation) and attenuates its ubiquitination. DDB1 is thus stabilized and degrades its downstream targets, such as c-Myc. We further utilized mouse xenograft models and demonstrated that PARG-S26A promoted HCC. Our study thus revealed that PARG O-GlcNAcylation inhibits HCC, and we propose that O-GlcNAc glycosylation may crosstalk with many other PTMs.
Project description:Pili on the surface of Sulfolobus islandicus are used for a host of functions, and serve as receptors for certain archaeal viruses. We find that these pili, when removed from cells, resist digestion by trypsin or pepsin, and survive boiling in SDS or 5M guanidinium-HCl. We have used cryo-EM to determine the structure of these filaments at 4.1 Å resolution. An atomic model was built by combining the map with bioinformatics without prior knowledge of the pilin sequence, an approach that should prove useful when looking at assemblies where all of the components may not be known. The atomic structure of the archaeal pilus was unusual due to almost a third of the residues being either threonine or serine and many hydrophobic surface residues. While the map showed specific glycosylation of only three residues, mass per unit length measurements suggested extensive glycosylation. We show that this extensive glycosylation renders these filaments soluble and provides the remarkable structural stability. We also show that the overall fold of the archaeal pilin is quite similar to archaeal flagellin, establishing common evolutionary origins.
Project description:Chickpea (Cicer arietinum L.) seed proteins show a lot of functional properties leading this leg-ume an interesting component for the development of protein-enriched foods. However, both in-depth proteomic investigation and structural characterization of chickpea proteins seed are still lacking. In this paper we report a detailed characterization of chickpea seed protein fraction by means SDS-PAGE, in-gel protein digestion, high-resolution mass spectrometry, and database searching. By this approach twenty SDS gel bands were cut and analysed. While the majority of bands and the identified peptides were related to vicilin and legumin storage proteins, also metabolic functional proteins were detected. Legumins, as expected, were revealed at 45÷65 kDa, as whole subunits with the α- and β-chains linked together by a disulphide bond, but also at lower mass ranges (α- and β-chains migrating alone). Similarly, but not expected, also the vi-cilins were spread along the mass region between 65 and 23 kDa, with some of them identified in several bands. In-depth MS structural characterization allowed to determine that, although chickpea vicilins were always described as proteins lacking of cysteine residues, they contain this amino acid residue. Moreover, similarly to legumins, these storage proteins are firstly syn-thesized as pre-propolypeptides (Mr 50÷80 kDa), that may undergo to proteolytic steps that cut not only the signal peptides but also produce different subunits having lower molecular masses. Overall, about 360 different proteins specific of the Cicer arietinum L. species were identified and characterized, a result that up to date represents the most detailed description of seed’s proteome of this legume.
Project description:Chaperone proteins are redundant in nature and, to achieve their function, they bind a large repertoire of client proteins. DnaK is a bacterial chaperone protein that recognizes misfolded and aggregated proteins and drives their folding and intracellular trafficking. Some Mycoplasmas are associated with cancers, and we demonstrated that infection with a strain of Mycoplasma fermentans isolated in our lab promoted lymphoma in a mouse model. Its DnaK is expressed intracellularly in infected cells, it interacts with key proteins to hamper essential pathways related to DNA repair and p53 functions and uninfected cells can take-up extracellular DnaK.