Project description:The urea channel Slc14a2 (or UT-A1) mediates vasopressin-regulated urea transport across the inner medullary collecting duct (IMCD). Previously, UT-A1 was found to present in a high molecular weight complex, suggesting UT-A1 is involved in certain protein-protein interactions. The present study sought to identify the proteins that interact with UT-A1 in this complex for a better understanding of how UT-A1 is regulated. Rat IMCD suspensions were treated with or without V2 receptor agonist, dDAVP, followed by in-cell crosslinking using BSOCOES and detergent solubilization. Immunoprecipitation using Dynabeads coated with UT-A1 specific antibody successfully pulled down the UT-A1 proteins. In-gel digestion protocol was carried out to prepare samples for liquid chromatographic mass spectrometry analysis of tryptic peptides using a Velos-Orbitrap mass spectrometer. The peptides passing stringent spectral quality thresholds were quantified (label-free) to identify those with (UTA-1 antibody/preimmune IgG) >4. A total of 128 UT-A1 interacting proteins were identified. Gene Ontology analysis maps the distribution of these proteins throughout major cell compartments: endoplasmic reticulum, Golgi, endosomes, cytosol and plasma membrane. Among them are four protein kinases (Cdc42bpb, Phkb, Camk2d, Mtor) that play roles in vasopressin-regulated phosphorylation of UT-A1. Non-label quantification was also performed to determine the stoichiometry of UT-A3 with UT-A1, the result does not support an oligomeric complex formation of UT-A1/A3. In conclusion, we have provided a refined list of UT-A1 binding proteins which can be useful for further analysis of the vasopressin signaling pathway in regulation of UT-A1 in IMCD.
Project description:Androgen receptor (AR)-targeting prostate cancer drugs, which are predominantly competitive ligand binding domain (LBD)-binding antagonists, are inactivated by common resistance -mechanisms. It is important to develop next-generation mechanistically-distinct drugs to treat castration- and drug- resistant prostate cancers. Here, we describe a second-generation AR pan-antagonist (UT-34) that degrades the AR and AR splice variants. UT-34 inhibits the wild-type and LBD mutant ARs comparably and inhibits the in vitro proliferation and in vivo growth of enzalutamide-sensitive and resistant prostate cancer xenografts. In preclinical models, UT-34 induced the regression of enzalutamide-resistant tumors at doses when the AR is degraded; but, at lower doses when the AR is just antagonized, it inhibits, without shrinking, the tumors. This indicates that degradation might be a prerequisite for tumor regression. Mechanistically, UT-34 promotes a conformation that is distinct from the LBD-binding competitive antagonist, enzalutamide, and degrades the AR through the ubiquitin proteasome mechanism. UT-34 has a broad safety margin and exhibits no cross-reactivity with G-Protein Coupled Receptor, kinase, and nuclear receptor family members. Collectively, UT-34 exhibits the properties necessary for a next-generation prostate cancer drug. MR49F cells (n=3-4/group) were maintained in charcoal-stripped serum containing medium for 48 hours and treated with vehicle, 0.1 nM R1881, or 10 uM of UT-34 in combination with 0.1 nM R1881. Twenty four hours after treatment, the cells were harvested, RNA was isolated and expression of genes was measured using microarray (Affymetrix Clarion S) UT-34 is a selective androgen receptor degrader that degrades and antagonizes the AR. UT-34 binds to the AF-1 domain of the AR and degrades the AR through ubiquitin proteasome pathways. The transcriptome study was performed to evaluate the ability of UT-34 to antagonize the enzalutamide-resistant AR function.
Project description:An important question for the use of the mouse as a model for studying human disease is the degree of functional conservation of genetic control pathways from human to mouse. The human and mouse placenta show structural similarities but there have been no systematic attempt to assess their molecular similarities or differences. We built a comprehensive database of protein and microarray data for the highly vascular exchange region micro-dissected from the human and mouse placenta near-term. Abnormalities in this region are associated with two of the most common and serious complications of human pregnancy, maternal preeclampsia (PE) and fetal intrauterine growth restriction (IUGR), each disorder affecting ~5% of all pregnancies. Over 7,000 orthologs were detected with 70% co-expressed and over 80% of genes known to cause placental phenotypes in mouse were co-expressed. These genes form a tight protein-protein interaction network with novel candidate genes likely to be important in placental structure and/or function. The entire data is available as a web-accessible database to guide the informed development of mouse models to study human disease This experiment is now fully represented in NCBI Peptidome database with accession PSE115; http://www.ncbi.nlm.nih.gov/peptidome/search/index.shtml?acc=PSE115 Microdissection of human villous trees and mouse placental labyrinth. Tissues were split for microarray and protein analysis. For protein analysis samples were first fractionated by differential sucrose gradients into mitochrondria, cytosol, microsomes and nuclei. Mitochrondira and neuclei were each extracted by two different methods for soluble and insoluble material. Each subcellular fraction for each tissue was analysed in quintuplet by 9 step 2 dimensional LC/MSMS. This generated a total of 270 mzXML files for each tissue.