How do proteins in our body achieve muscle movement?

This poster provides an introduction into the studies of proteins, involved in muscle movement and contraction, that we are undertaking at the ANU's John Curtin School of Medical Research. We study interactions between these proteins on a molecular level, with the aim of better understanding of physiological processes that take place in our muscle cells under normal conditions and in disease states. The outcomes of our research might pave the way for the treatment of pathological conditions, associated with skeletal and cardiac muscle disorders.NHMRC APP112620

Innovative Method for the Estimation of Closure Velocity between RAT Driven Drogue and IFR Probe Air to Air refueling Flight Trials

Air-to-air refueling for a fighter platform is a force multiplier in terms of increasing its combat radius and payload carrying ability. Adapting for such a facility especially for an aircraft under design and development is a challenging task. It requires rigorous ground and flight testing to meet the certification standards. One of important flight test parameter that needs to be validated for structural impact load calculations and certification needs is the closure velocity. The air-to-air refueller was equipped with a Ram-air-turbine powered drogue and chute system. An innovative methodology of estimating the closure velocity between the drogue of the mother aircraft and the in-flight refueling probe of the receiving aircraft was evolved. The method was employed and validated during the air-to-air refueling trials of a prototype fighter platform. The intention of this paper is to explain the methodology employed and deliberate the results obtained with respect to the air-to-air refueling certification

Glutathione Transferase Omega-1 Regulates NLRP3 Inflammasome Activation through NEK7 Deglutathionylation

The NLRP3 inflammasome is a cytosolic complex sensing phagocytosed material and various damage-associated molecular patterns, triggering production of the pro-inflammatory cytokines interleukin-1 beta (IL)-1β and IL-18 and promoting pyroptosis. Here, we characterize glutathione transferase omega 1-1 (GSTO1-1), a constitutive deglutathionylating enzyme, as a regulator of the NLRP3 inflammasome. Using a small molecule inhibitor of GSTO1-1 termed C1-27, endogenous GSTO1-1 knockdown, and GSTO1-1−/− mice, we report that GSTO1-1 is involved in NLRP3 inflammasome activation. Mechanistically, GSTO1-1 deglutathionylates cysteine 253 in NIMA related kinase 7 (NEK7) to promote NLRP3 activation. We therefore identify GSTO1-1 as an NLRP3 inflammasome regulator, which has potential as a drug target to limit NLRP3-mediated inflammation.We would like to acknowledge the following grants: the National Health and Medical Research Council of Australia (NHMRC) is thanked for Project Grant APP1124673 to P.G.B., M.G.C., and L.A.J.O.; Principal Research Fellowship 1117602 to J.B.B.; and NHMRC Project Grant APP1156455 to J.B.B., P.G.B., and M.G.C. The O’Neill laboratory acknowledges the following grant support: European Research Council (ECFP7-ERC-MICROINNATE) and Science Foundation Ireland Investigator Award (SFI 12/IA/1531)

Differing roles of CD1d2 and CD1d1 proteins in type I natural killer T cell development and function

MHC class I-like CD1 molecules have evolved to present lipid-based antigens to T cells. Differences in the antigen-binding clefts of the CD1 family members determine the conformation and size of the lipids that are presented, although the factors that shape CD1 diversity remain unclear. In mice, two homologous genes, CD1D1 and CD1D2, encode the CD1d protein, which is essential to the development and function of natural killer T (NKT) cells. However, it remains unclear whether both CD1d isoforms are equivalent in their antigen presentation capacity and functions. Here, we report that CD1d2 molecules are expressed in the thymus of some mouse strains, where they select functional type I NKT cells. Intriguingly, the T cell antigen receptor repertoire and phenotype of CD1d2-selected type I NKT cells in CD1D1−/− mice differed from CD1d1-selected type I NKT cells. The structures of CD1d2 in complex with endogenous lipids and a truncated acyl-chain analog of α-galactosylceramide revealed that its A′-pocket was restricted in size compared with CD1d1. Accordingly, CD1d2 molecules could not present glycolipid antigens with long acyl chains efficiently, favoring the presentation of short acyl chain antigens. These results indicate that the two CD1d molecules present different sets of self-antigen(s) in the mouse thymus, thereby impacting the development of invariant NKT cells

Molecular insights into lipid-based antigen recognition by Natural Killer T cell antigen receptors

Our body comprises a group of defense warriors that protect us from the infections caused by microbes such as bacteria and viruses. These soldiers typically sense the proteins present in microbes to execute their functions. Recently, a special group of defense warriors was identified which senses fats from microorganisms for their protective function. In this PhD thesis, the structural basis underpinning how these specialized warriors recognize microbial fats and its influence on the outcome of numerous medical conditions have been examined

1H, 13C and 15N backbone NMR chemical shift assignments of the C-terminal P4 domain of Ahnak

Ahnak is a ~ 700 kDa polypeptide that was originally identified as a tumour-related nuclear phosphoprotein, but later recognized to play a variety of diverse physiological roles related to cell architecture and migration. A critical function of Ahnak is modulation of Ca2+ signaling in cardiomyocytes by interacting with the β subunit of the L-type Ca2+ channel (CaV1.2). Previous studies have identified the C-terminal region of Ahnak, designated as P3 and P4 domains, as a key mediator of its functional activity. We report here the nearly complete 1H, 13C and 15N backbone NMR chemical shift assignments of the 11 kDa C-terminal P4 domain of Ahnak. This study lays the foundations for future investigations of functional dynamics, structure determination and interaction site mapping of the CaV1.2-Ahnak complex

Predicted interactions between the prodomain and the mature domain of FP2 and FP3.

<p><b>A.</b> Close up of predicted interactions between the mature enzyme and the ERFNIN and GNFD motifs of the prodomain (Arg ¹⁸⁵ - Glu ²²¹, and Phe ²¹⁴-Trp⁴⁴⁹/Trp ⁴⁵³, Glu ²¹⁰ - Lys ⁴⁰³). Blue dashed lines indicate presumed stabilizing interactions between residues in FP2. <b>B.</b> Blue dashed lines indicate presumed stabilizing interactions (Arg ²⁰²-Glu²³⁸ and Phe ²³¹-Trp⁴⁵⁷/Trp461) between the residues in FP3.</p

Role of salt bridge and hydrophobic interactions in FP2.

<p><b>A.</b> The mutated enzyme (Glu ²²¹) was expressed in <i>E.Coli</i>, purified and refolded, and finally processed and compare with wild FP2, analyzed by SDS-PAGE and Western blot. <b>B.</b> Two other mutants (Glu ²¹⁰ and Phe ²¹⁴) were also expressed in <i>E.coli</i>, purified and refolded. The processing of those mutants was further analyzed by SDS-PAGE and Western blot analysis. The uninduced <i>E.Coli</i> lysates was used as a negative control. <b>C.</b> The wild FP2 and mutated enzymes (Glu ²²¹, Glu ²¹⁰, Asp ¹⁵¹, Phe ²¹⁴) were processed and subjected to gelatin substrate native PAGE, and assessed their functional activity.</p