Although signals for retention in the endoplasmic reticulum (ER) have been identified cytoplasmic domain of various ER-resident type I transmembrane proteins, mechanisms responsible ER are still unknown. Yeast and mammalian motifs interacted specifically cell lysates with coatomer, a polypeptide complex implicated membrane traffic. Mutations that affect capacity also abolished binding coatomer. These results suggest role coatomer retrieval proteins to both yeast mammals.

The multichain T cell antigen receptor functions by interacting with and activating one or more nonreceptor tyrosine kinases. cytoplasmic tail of the ζ chain can activate cells independently rest complex. function remaining invariant CD3 chains remains unknown. A 22-amino acid region ε was also able to cells. Stimulation means tails either resulted in quantitatively distinct patterns phosphorylation, suggesting activation different biochemical pathways.

The zeta chain of the T-cell antigen receptor is prototype a family proteins that exist as disulfide-linked dimers and are subunits both IgE IgG binding Fc receptors. Two related genes encode gamma proteins. In this study we examine ability chimeric consisting extracellular domain alpha interleukin 2 (Tac) cytoplasmic either or to activate cells when expressed in T rat basophilic leukemia cells. chimera were effective at eliciting production serotonin release externally cross-linked....

To identify the molecular mechanisms involved in phagocytosis, we generated random insertion mutants of<i>Dictyostelium discoideum</i> and selected two defective for phagocytosis. Both represented insertions same gene, named<i>PHG1</i>. This gene encodes a polytopic membrane protein with an N-terminal lumenal domain nine potential transmembrane segments. Homologous genes can be identified many species; however, their function is yet to elucidated. Disruption of <i>PHG1</i> caused selective...

We investigated the phenotypic and genotypic susceptibility of 11 human immunodeficiency virus type 1 (HIV-1) group O strains to nucleoside nonnucleoside reverse transcriptase (RT) inhibitors protease in vitro. Phenotypic was determined by using a standardized vitro assay RT inhibition, taking into account replication kinetics each strain. HIV-1 M HIV-2 isolates were used as references. DNA from cocultured peripheral blood mononuclear cells amplified pol-specific primers cloned for...

Abstract We have isolated a variant of the DO‐11.10.7 mouse T cell hybridoma which does not express functional receptor α/β chains. This variant, denoted 58 α − β , can be used as recipient for gene transfer experiments to obtain lines only products transfected genes at their surfaces. In process characterizing defects affecting genes, we found that parental BW5147 thymoma has undergone previously unnoticed V ‐J rearrangement. rearrangement involves pseudogene segment and accounts high level...

The tyrosine-based activation motif is a 20- to 25-amino-acid sequence contained in the cytoplasmic domains of many hematopoietic receptors which sufficient by itself reconstitute signalling. This characterized two YXXL/I sequences separated approximately 10 residues. molecular basis signalling this unknown. Here we demonstrate that required and for association with tyrosine kinases p59fyn ZAP-70, suggesting these general feature motif. Focusing on single present epsilon, analyzed residues...

COPII proteins are necessary to generate secretory vesicles at the endoplasmic reticulum. In yeast, Sec24p protein is only component in which two close orthologues have been identified. By using gene knock-out we found that absence of one these Sec24 resulted a selective secretion defect for subset released into medium. Data base searches revealed existence an entire family Sec24-related humans, worms, flies, and plants. We identified cloned new human cDNAs encoding homologous yeast Sec24p,...

Signals that can cause retention in the ER have been found cytoplasmic domain of individual subunits multimeric receptors destined to cell surface. To study how motifs are masked during assembly oligomeric receptors, we analyzed and intracellular transport human high-affinity receptor for immunoglobulin E expressed COS cells. The alpha chain contains a dilysine signal, which becomes nonfunctional after with gamma chain, allowing out fully assembled receptor. Juxtaposition domains is...

Abstract Legionella pneumophila can cause Legionnaires’ disease and replicates intracellularly in a distinct -containing vacuole (LCV). LCV formation is complex process that involves plethora of type IV-secreted effector proteins. The RidL binds the Vps29 retromer subunit, blocks retrograde vesicle trafficking, promotes intracellular bacterial replication. Here, we reveal 29-kDa N-terminal domain (RidL 2–281 ) adopts “foot-like” fold comprising protruding β-hairpin at its “heel”. deletion...

In T lymphocytes, signal transduction through the CD2 adhesion molecule requires surface expression of CD3-Ti T-cell receptor (TCR) complex. contrast, in natural killer (NK) cells, functions absence a TCR. Because TCR on lymphocytes and CD16 low-affinity IgG Fc (Fc gamma type III) complex NK cells share common CD3 zeta subunit, we reasoned that may be critical for signaling cells. Here show transfection cDNA encoding transmembrane form into TCR- variants Jurkat line results association with...

Specialized eukaryotic cells can ingest large particles and sequester them within membrane-delimited phagosomes. Many studies have described the delivery of lysosomal proteins to phagosome, but little is known about membrane sorting during early stages phagosome formation. Here we used Dictyostelium discoideum amoebae analyze composition newly formed The delimiting closing phagocytic cup was essentially derived from plasma membrane, a subgroup specifically excluded. Interestingly same...

Sorting of ubiquitinated proteins to multivesicular bodies (MVBs) in mammalian cells relies on with a Vps27/Hrs/STAM (VHS) domain. Here, we show that the amoeba Dictyostelium presents only one protein VHS domain: DdTom1. We demonstrate domain DdTom1 is followed by Golgi-localized, gamma-ear-containing, ADP-ribosylation-factor-binding and Tom1 (GAT) binds ubiquitin, non-conserved C-terminal can recruit clathrin, EGFr pathway substrate 15 tumor susceptibility gene 101, component MVB biogenesis...

The causative agent of Legionnaires’ disease, Legionella pneumophila , is an amoebae-resistant environmental bacterium, which replicates intracellularly in a distinct compartment, the “ -containing vacuole” (LCV). L. employs α-hydroxyketone compound LAI-1 ( autoinducer-1) for intra-species and inter-kingdom signaling. promotes intracellular replication inhibits migration mammalian cells Dictyostelium discoideum . In this study, we revealed that “clickable” azido-LAI-1 derivatives inhibit D....