Project description:This project consists of two experiments. The first is mapping the binding interface between the isolated m-lip domain of mouse lipin and liposomes. The second experiments is mapping the binding interface between full length mouse lipin and liposomes. Looking at the isolated m-lip domain, we found that residues 470-490 and 500-550 showed decreases in exchange upon liposome binding. The full-length lipin experiment saw decreases in exchnage in these same regions, as well as in the very C-terminus and very N-terminus regions of the protein. An order-disorder experiment was done on full length lipin where the protein was exposed to a short pulse of deuterium and compared to the fully-deuterated protein. In this instance, we established that the majority of the protein is relatively disordered and does not have secondary structure with high stability
Project description:The class IB phosphoinositide 3-kinase (PI3K), PI3K, is a master regulator of immune cell function, and is a promising drug target for both inflammatory diseases and cancer. Critical to PI3K function is the association of the p110 catalytic subunit to either a p101 or p84 regulatory subunit, which mediates regulation by G-protein coupled receptors (GPCRs). Here, we report the first structure of a heterodimeric PI3K complex, p110-p101. This structure revealed a unique mode of assembly of catalytic and regulatory subunits distinct from that of other class I PI3K complexes. Multiple oncogenic mutations mapped to these novel interfaces led to increased activation by G. p101 mediates activation through its G binding domain, recruiting the complex to the membrane and allowing for engagement of a secondary site in p110. A nanobody that specifically binds to this p101-G interface blocks activation providing a novel tool to study p101-specific signaling events in vivo.
Project description:We used Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS) to examine the dynamic structural changes caused by oncogenic mutations. We performed HDX-MS comparing the full-length complex against the catalytic core which suggest that addition of pY leads to mixed two state population where the state 1 consists of iSH2 bound p110α and the state 2 consists of p110α where the iSH2 is completely disengaged.Therefore, we propose that the non-kinase domain mutations push the equilibrium towards state 2 leading to enhanced enzyme activity.We also propose that the kinase domain mutations lead to the re-orientation of the c-terminal tail leading to exposure of the activation loop and enhanced membrane binding.
Project description:Use of HDX-MS to study the allosteric and structural differences between the TRAPPII and TRAPPIII complex in the presence and absence of membrane and rab GTPases
Project description:This project consisted of three HDX-MS experiments. First, we compared the dimeric PDK1(SKD-PIF) to monomeric PDK1(SKD) and mapped the differences in deuterium incorporation onto the dimer model. We then compared the deuterium incorporation kinetics for the kinase (PDK1(SKD)) and PH (PDK1(PH) domains of PDK1 with full-length PDK1 (PDK1(FL)) in pairwise experiments.
Project description:We use HDX-MS to interrogate the AKT1 DrLink conformational changes upon binding AKT1 active site inhibitors A-443654, Capivasertib, and Uprosertib, Akt1 allosteric inhibitor MK-2206, and ADP.
Project description:We carried out 4 HDX-MS experiments to investigate the ARMH3 interactions with PI4Kb, Arl5b(GTPyS) and GBF1 (ARMH3+Arl5b, ARMH3+GBF1(1-709)) and ARMH3+GBF1(364-395)). Analysis of these four experiments defined the Arl5b intereface on ARMH3 and defined the disordered linker region located in the DCB-HUS domains region of GBF1 (residues 364-395) as the ARMH3 binding region (ABR)
Project description:We used HDX-MS to map novel binding sites of calcineurin on PI4KA and FAM126A. Calcineurin binds to PxIxIT and LxVP motifs on PI4KA and FAM126A indicating a novel regulatory mechanism of Pi4KA by calcineurin