Project description:Focal adhesion kinase (FAK) is an attractive drug target due to its overexpression in cancer. FAK functions as a non-receptor tyrosine kinase and scaffolding protein, coordinating several downstream signaling effectors and cellular processes. While drug discovery efforts have largely focused on targeting FAK kinase activity, FAK inhibitors have failed to show efficacy as single agents in clinical trials. Here, using structure-guided design, we report the development of a selective FAK inhibitor (BSJ-04-175) and degrader (BSJ-04-146) to evaluate the consequences and advantages of abolishing all FAK activity in cancer models. BSJ-04-146 achieves rapid and potent FAK degradation with high proteome-wide specificity in cancer cells and induces remarkably durable degradation in tumor-bearing mice. Compared to kinase inhibition, targeted degradation of FAK exhibits pronounced improved activity on downstream signaling and cancer cell viability and migration. Together, BSJ-04-175 and BSJ-04-146 are valuable chemical tools to dissect the specific consequences of targeting FAK through small molecule inhibition or degradation.
Project description:We sought to build a catalog of epitopes presented by breast cancers using a renewable resource of well-characterized breast cancer cell lines. Starting from 70 breast cancer cell lines, we measured MHC class I abundance and used pre-existing RNAseq data to identify either HLA-A*02 or MHC class I-positive cell lines. For 20 of these cell lines, we used “reverse” immunogenetics, in which MHC class I-loaded peptides are recovered and their sequences are determined by mass spectrometry. We identified more than 2,700 unique MHC class I-bound peptides from a panel of basal, luminal, and claudin-low subtype of cell lines. HLA-A*02 binding prediction across all tested cell lines revealed a model which described the distribution of HLA-A*02-binding peptides and allowed us to identify those peptides most likely to be presented on HLA-A*02. Comparing the peptides that we identified to published literature found that more than 1500 peptides had been identified in previous studies and that 18 of these peptides have been shown to be immunogenic. Overall, this high throughput identification of MHC class I-loaded peptides is an effective strategy for systematic characterization of cancer epitopes and could be employed in a design of multipeptide-based anticancer vaccine.
Project description:Ataxia telangiectasia mutated (ATM) is a protein that belongs to the family of phosphatidylinositol 3-kinase (PI3K)-like serine/threonine kinases. Initially identified as a nuclear protein essential for the DNA damage response (DDR) in mitotic cells, it serves as repair coordinator for DNA double-strand breaks (DSBs). Dysfunction of the ATM protein underlies ataxia telangiectasia (A-T), a rare autosomal recessive disorder characterized by immunodeficiency and progressive cerebellar degeneration leading to ataxia. The cause of cerebellar neurodegeneration cannot be explained at present, given that in postmitotic neurons ATM has a cytoplasmic localization. The non-nuclear functions of ATM and their mechanistic link to cerebellar degeneration in A-T remain elusive. In this study we established both phosphoproteomic and proteomic profiles of ATM deficiency in neuroblastoma cells and mouse cerebellum tissue to identify the underlying molecular mechanism and relevant signaling networks.
Project description:Comparison of expression profile of two 3D7 isogenic clones : 3D7AH1S2 and 3D7S8.4 at three different stages of intraerythrocytic cycle: ring, trophozite and schizont stage
Project description:We developed a simple, antibody-free approach for single shot analysis of tau phosphorylation across the entire protein by liquid-chromatography tandem mass spectrometry (LC-MS/MS) to study age-related changes in tau phosphorylation. This methodology is species independent; thus, while initially developed in a rodent model, we utilized this technique to analyze 36 phosphorylation sites on rhesus monkey tau from the prefrontal cortex (PFC), a region vulnerable to AD degeneration. We identified novel, age-related changes in tau phosphorylation in the rhesus monkey PFC and analyzed patterns of phosphorylation change across domains of the protein. We confirmed a significant increase and positive correlation with age of phosphorylated serine235 tau and phosphorylated serine396 tau levels in an expanded cohort of 14 monkeys.
Project description:Vasopressin/cAMP/protein kinase A (PKA) signaling phosphorylates AQP2 water channels in renal collecting ducts to reabsorb water from urine for the prevention of further water loss. Lipopolysaccharide-responsive and beige-like anchor protein (LRBA) mediates vasopressin-induced AQP2 phosphorylation; therefore LRBA is essential for urinary concentration. LRBA is identified as the PKA substrates in a mouse cortical collecting duct principal cell line (mpkCCDcl4) whose phosphorylation levels are nearly perfectly correlated with those of AQP2. Although mouse LRBA contains several consensus PKA phosphorylation sites, their phosphorylation status in response to vasopressin remain unknown. Post-translational modification analysis revealed that RRDS1607 and RRIS2189 were phosphorylated by vasopressin.
Project description:ATR is a PI3K-like kinase protein, regulating checkpoint responses to DNA damage and replication stress. Apart from its checkpoint function in the nucleus, ATR actively engage in antiapoptotic role at mitochondria following DNA damage. The different functions of ATR in the nucleus and cytoplasm are carried out by two prolyl isomeric forms of ATR: trans- and cis-ATR, respectively. The isomerization occurs at the Pin1 Ser428-Pro429 motif of ATR. Here we investigated the structural basis of the subcellular location-specific functions of human ATR. Using a mass spectrometry-based footprinting approach, the surface accessibility of ATR lysine residues to sulfo-NHS-LC-biotin modification was monitored and compared between the cis and the trans-isomers. We have identified two biotin-modified lysine residues, K459 and K469, within the BH3-like domain of cis-ATR that were not accessible in trans-ATR, indicating a conformational change around the BH3 domain between cis- and trans-ATR. The conformational alteration also involved the N-terminal domain and the middle HEAT domain. Moreover, experimental results from an array of complementary assays show that cis-ATR with the accessible BH3 domain was able to bind to tBid while trans-ATR could not. In addition, both cis- and trans-ATR can directly form homodimers via their C-terminal domains without ATRIP, while nuclear (trans-ATR) in the presence of ATRIP forms dimer-dimer complexes involving both N- and C-termini of ATR and ATRIP after UV. Structural characteristics around the Ser428-Pro429 motif and the BH3 domain region are also analyzed by molecular modelling and dynamics simulation. In support, cis conformation was found to be significantly more energetically favourable than trans at Ser428-Pro429 bond in a 20-aa wild-type ATR peptide. Taken together, our results suggest that the isomerization-induced structural changes of ATR define both its subcellular location and compartment-specific functions and plays an essential role in promoting cell survival and DNA damage responses.
Project description:Actin was acetylated on lysine residues with acetic anhydride to determine its impaction on the contractile properties of the thin filaments including, actin's ability to undergo crossbridge cycling with myosin, actin's affinity for tropomyosin, and the impact of actin acetylation on calcium regulated thin filament activation