Publications by authors named "Philip Achacoso"

4 Publications

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Non-catalytic ubiquitin binding by A20 prevents psoriatic arthritis-like disease and inflammation.

Nat Immunol 2020 04 16;21(4):422-433. Epub 2020 Mar 16.

Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.

A20 is an anti-inflammatory protein that is strongly linked to human disease. Here, we find that mice expressing three distinct targeted mutations of A20's zinc finger 7 (ZF7) ubiquitin-binding motif uniformly developed digit arthritis with features common to psoriatic arthritis, while mice expressing point mutations in A20's OTU or ZF4 motifs did not exhibit this phenotype. Arthritis in A20 mice required T cells and MyD88, was exquisitely sensitive to tumor necrosis factor and interleukin-17A, and persisted in germ-free conditions. A20 cells exhibited prolonged IκB kinase activity that drove exaggerated transcription of late-phase nuclear factor-κB response genes in vitro and in prediseased mouse paws in vivo. In addition, mice expressing double-mutant A20 proteins in A20's ZF4 and ZF7 motifs died perinatally with multi-organ inflammation. Therefore, A20's ZF4 and ZF7 motifs synergistically prevent inflammatory disease in a non-catalytic manner.
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http://dx.doi.org/10.1038/s41590-020-0634-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7195210PMC
April 2020

A20 and ABIN-1 synergistically preserve intestinal epithelial cell survival.

J Exp Med 2018 07 21;215(7):1839-1852. Epub 2018 Jun 21.

Department of Medicine, University of California, San Francisco, San Francisco, CA

A20 () and ABIN-1 () are candidate susceptibility genes for inflammatory bowel disease and other autoimmune or inflammatory diseases, but it is unclear how these proteins interact in vivo to prevent disease. Here we show that intestinal epithelial cell (IEC)-specific deletion of either A20 or ABIN-1 alone leads to negligible IEC loss, whereas simultaneous deletion of both A20 and ABIN-1 leads to rapid IEC death and mouse lethality. Deletion of both A20 and ABIN-1 from enteroids causes spontaneous cell death in the absence of microbes or hematopoietic cells. Studies with enteroids reveal that A20 and ABIN-1 synergistically restrict death by inhibiting TNF-induced caspase 8 activation and RIPK1 kinase activity. Inhibition of RIPK1 kinase activity alone, or caspase inhibition combined with RIPK3 deletion, abrogates IEC death by blocking both apoptosis and necroptosis in A20 and ABIN-1 double-deficient cells. These data show that the disease susceptibility proteins A20 and ABIN-1 synergistically prevent intestinal inflammation by restricting IEC death and preserving tissue integrity.
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http://dx.doi.org/10.1084/jem.20180198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6028510PMC
July 2018

Measurements of β-arrestin recruitment to activated seven transmembrane receptors using enzyme complementation.

Methods Mol Biol 2012 ;897:181-203

DiscoveRx Corporation, Fremont, CA, USA.

The recruitment of arrestins to activated 7TMRs results in the activation of alternative signaling pathways, quenching of G-protein activation, and coupling to clathrin-mediated endocytosis. The nearly ubiquitous involvement of arrestin in 7TMR signaling has spurred the development of several methods for monitoring this interaction in mammalian cells. Nonetheless, few maintain the reproducibility and precision necessary for drug discovery applications. Enzyme fragment complementation technology (EFC) is an emerging protein-protein interaction technology based on the forced complementation of a split enzyme that has proven to be highly effective in monitoring the formation of GPCR-arrestin complexes. In these systems, the target proteins are fused to two fragments of an enzyme that show little or no spontaneous complementation. Interaction of the two proteins forces the complementation of the enzyme, resulting in an enzymatic measure of the protein interaction. This chapter discusses the utility and methods involved in using the PathHunter β-galactosidase complementation system to monitor arrestin recruitment and the advantages of exploiting this pathway in the characterization of 7TMR function.
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http://dx.doi.org/10.1007/978-1-61779-909-9_9DOI Listing
October 2012

Discovery and characterization of substituted diphenyl heterocyclic compounds as potent and selective inhibitors of hepatitis C virus replication.

Antimicrob Agents Chemother 2008 Apr 28;52(4):1419-29. Epub 2008 Jan 28.

Department of Virology, Rigel Pharmaceuticals, Inc., 1180 Veterans Boulevard, South San Francisco, CA 94080, USA.

A novel small-molecule inhibitor, referred to here as R706, was discovered in a high-throughput screen of chemical libraries against Huh-7-derived replicon cells carrying autonomously replicating subgenomic RNA of hepatitis C virus (HCV). R706 was highly potent in blocking HCV RNA replication as measured by real-time reverse transcription-PCR and Western blotting of R706-treated replicon cells. Structure-activity iterations of the R706 series yielded a lead compound, R803, that was more potent and highly specific for HCV replication, with no significant inhibitory activity against a panel of HCV-related positive-stranded RNA viruses. Furthermore, HCV genotype 1 replicons displayed markedly higher sensitivity to R803 treatment than a genotype 2a-derived replicon. In addition, R803 was tested by a panel of biochemical and cell-based assays for on-target and off-target activities, and the data suggested that the compound had a therapeutic window close to 100-fold, while its exact mechanism of action remained elusive. We found that R803 was more effective than alpha interferon (IFN-alpha) at blocking HCV RNA replication in the replicon model. In combination studies, R803 showed a weak synergistic effect with IFN-alpha/ribavirin but only additive effects with a protease inhibitor and an allosteric inhibitor of RNA-dependent RNA polymerase (20). We conclude that R803 and related heterocyclic compounds constitute a new class of HCV-specific inhibitors that could potentially be developed as a treatment for HCV infection.
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http://dx.doi.org/10.1128/AAC.00525-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2292530PMC
April 2008