Torrey Pines Institute for Molecular Studies

About: Torrey Pines Institute for Molecular Studies is a nonprofit organization based out in San Diego, California, United States. It is known for research contribution in the topics: Antigen & T cell. The organization has 2323 authors who have published 2217 publications receiving 112618 citations.

Dynamic caveolae exclude bulk membrane proteins and are required for sorting of excess glycosphingolipids

Abstract: Caveolae have long been implicated in endocytosis. Recent data question this link, and in the absence of specific cargoes the potential cellular function of caveolar endocytosis remains unclear. Here we develop new tools, including doubly genome-edited cell lines, to assay the subcellular dynamics of caveolae using tagged proteins expressed at endogenous levels. We find that around 5% of the cellular pool of caveolae is present on dynamic endosomes, and is delivered to endosomes in a clathrin-independent manner. Furthermore, we show that caveolae are indeed likely to bud directly from the plasma membrane. Using a genetically encoded tag for electron microscopy and ratiometric light microscopy, we go on to show that bulk membrane proteins are depleted within caveolae. Although caveolae are likely to account for only a small proportion of total endocytosis, cells lacking caveolae show fundamentally altered patterns of membrane traffic when loaded with excess glycosphingolipid. Altogether, these observations support the hypothesis that caveolar endocytosis is specialized for transport of membrane lipid.

Recognition of conserved amino acid motifs of common viruses and its role in autoimmunity.

Abstract: The triggers of autoimmune diseases such as multiple sclerosis (MS) remain elusive. Epidemiological studies suggest that common pathogens can exacerbate and also induce MS, but it has been difficult to pinpoint individual organisms. Here we demonstrate that in vivo clonally expanded CD4+ T cells isolated from the cerebrospinal fluid of a MS patient during disease exacerbation respond to a poly-arginine motif of the nonpathogenic and ubiquitous Torque Teno virus. These T cell clones also can be stimulated by arginine-enriched protein domains from other common viruses and recognize multiple autoantigens. Our data suggest that repeated infections with common pathogenic and even nonpathogenic viruses could expand T cells specific for conserved protein domains that are able to cross-react with tissue-derived and ubiquitous autoantigens.

Direct Evidence from Single-Cell Analysis that Human α-Defensins Block Adenovirus Uncoating To Neutralize Infection

Abstract: Human α-defensins are evolutionarily conserved effectors of the innate immune response with broadly acting antibacterial activity. Their role in antiviral immunity is less well understood. We previously showed that these antimicrobial peptides are potent inhibitors of human adenovirus infection. Based on biochemical studies and indirect evidence from confocal microscopy, we proposed that defensins bind to and stabilize the virus capsid and neutralize infection by preventing the release of the endosomalytic protein VI. To determine whether defensin action also restricts exposure of the viral genome, we developed a system to evaluate adenovirus uncoating during cell entry by monitoring the exposure of BrdU-labeled viral genomes. This assay allowed us to determine the kinetics of uncoating of virus particles in single cells. Using this assay, we now provide direct evidence that human α-defensins block adenovirus infection by preventing uncoating during cell entry.