scholarly journals Microtubule-dependent endosomal sorting of clathrin-independent cargo by Hook1

2013 ◽  
Vol 201 (2) ◽  
pp. 233-247 ◽  
Author(s):  
Lymarie Maldonado-Báez ◽  
Nelson B. Cole ◽  
Helmut Krämer ◽  
Julie G. Donaldson
Keyword(s):  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Cell Spreading ◽  
Complex Class ◽  
Present Evidence ◽  
Endosomal Sorting ◽  
Histocompatibility Complex ◽  
Cargo Protein ◽  
Cargo Proteins ◽  
Bulk Membrane

Many plasma membrane (PM) proteins enter cells nonselectively through clathrin-independent endocytosis (CIE). Here, we present evidence that cytoplasmic sequences in three CIE cargo proteins—CD44, CD98, and CD147—were responsible for the rapid sorting of these proteins into endosomal tubules away from endosomes associated with early endosomal antigen 1 (EEA1). We found that Hook1, a microtubule- and cargo-tethering protein, recognized the cytoplasmic tail of CD147 to help sort it and CD98 into Rab22a-dependent tubules associated with recycling. Depletion of Hook1 from cells altered trafficking of CD44, CD98, and CD147 toward EEA1 compartments and impaired the recycling of CD98 back to the PM. In contrast, another CIE cargo protein, major histocompatibility complex class I, which normally traffics to EEA1 compartments, was not affected by depletion of Hook1. Loss of Hook1 also led to an inhibition of cell spreading, implicating a role for Hook1 sorting of specific CIE cargo proteins away from bulk membrane and back to the PM.

scholarly journals MARCH ubiquitin ligases alter the itinerary of clathrin-independent cargo from recycling to degradation

2011 ◽  
Vol 22 (17) ◽  
pp. 3218-3230 ◽  
Author(s):  
Craig A. Eyster ◽  
Nelson B. Cole ◽  
Shariska Petersen ◽  
Kasinath Viswanathan ◽  
Klaus Früh ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Early Endosome ◽  
Complex Class ◽  
Histocompatibility Complex ◽  
Late Endosomes ◽  
Cargo Proteins ◽  
Reduced Surface

Following endocytosis, internalized plasma membrane proteins can be recycled back to the cell surface or trafficked to late endosomes/lysosomes for degradation. Here we report on the trafficking of multiple proteins that enter cells by clathrin-independent endocytosis (CIE) and determine that a set of proteins (CD44, CD98, and CD147) found primarily in recycling tubules largely failed to reach late endosomes in HeLa cells, whereas other CIE cargo proteins, including major histocompatibility complex class I protein (MHCI), trafficked to both early endosome antigen 1 (EEA1) and late endosomal compartments in addition to recycling tubules. Expression of the membrane-associated RING-CH 8 (MARCH8) E3 ubiquitin ligase completely shifted the trafficking of CD44 and CD98 proteins away from recycling tubules to EEA1 compartments and late endosomes, resulting in reduced surface levels. Cargo affected by MARCH expression, including CD44, CD98, and MHCI, still entered cells by CIE, suggesting that the routing of ubiquitinated cargo occurs after endocytosis. MARCH8 expression led to direct ubiquitination of CD98 and routing of CD98 to late endosomes/lysosomes.

scholarly journals Ebolavirus Glycoprotein GP Masks both Its Own Epitopes and the Presence of Cellular Surface Proteins

2009 ◽  
Vol 83 (18) ◽  
pp. 9596-9601 ◽  
Author(s):  
Olivier Reynard ◽  
Malgorzata Borowiak ◽  
Valentina A. Volchkova ◽  
Sebastien Delpeut ◽  
Mathieu Mateo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Mortality Rate ◽  
Hemorrhagic Fever ◽  
Surface Proteins ◽  
Surface Markers ◽  
Illusory Effect ◽  
Complex Class ◽  
Histocompatibility Complex ◽  
Antigenic Epitopes

ABSTRACT Ebolavirus (EBOV) is the etiological agent of a severe hemorrhagic fever with a high mortality rate. The spike glycoprotein (GP) is believed to be one of the major determinants of virus pathogenicity. In this study, we demonstrated the molecular mechanism responsible for the downregulation of surface markers caused by EBOV GP expression. We showed that expression of mature GP on the plasma membrane results in the masking of cellular surface proteins, including major histocompatibility complex class I. Overexpression of GP also results in the masking of certain antigenic epitopes on GP itself, causing an illusory effect of disappearance from the plasma membrane.

scholarly journals CD9 Regulates Major Histocompatibility Complex Class II Trafficking in Monocyte-Derived Dendritic Cells

2017 ◽  
Vol 37 (15) ◽  
Author(s):  
Vera Rocha-Perugini ◽  
Gloria Martínez del Hoyo ◽  
José María González-Granado ◽  
Marta Ramírez-Huesca ◽  
Virginia Zorita ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Antigen Presentation ◽  
T Cell Activation ◽  
Cell Activation ◽  
Complex Class ◽  
Gm Csf ◽  
Mhc Ii ◽  
Histocompatibility Complex

ABSTRACT Antigen presentation by dendritic cells (DCs) stimulates naive CD4+ T cells, triggering T cell activation and the adaptive arm of the immune response. Newly synthesized major histocompatibility complex class II (MHC-II) molecules accumulate at MHC-II-enriched endosomal compartments and are transported to the plasma membrane of DCs after binding to antigenic peptides to enable antigen presentation. In DCs, MHC-II molecules are included in tetraspanin-enriched microdomains (TEMs). However, the role of tetraspanin CD9 in these processes remains largely undefined. Here, we show that CD9 regulates the T cell-stimulatory capacity of granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent bone marrow-derived DCs (BMDCs), without affecting antigen presentation by fms-like tyrosine kinase 3 ligand (Flt3L)-dependent BMDCs. CD9 knockout (KO) GM-CSF-dependent BMDCs, which resemble monocyte-derived DCs (MoDCs), induce lower levels of T cell activation than wild-type DCs, and this effect is related to a reduction in MHC-II surface expression in CD9-deficient MoDCs. Importantly, MHC-II targeting to the plasma membrane is largely impaired in immature CD9 KO MoDCs, in which MHC-II remains arrested in acidic intracellular compartments enriched in LAMP-1 (lysosome-associated membrane protein 1), and MHC-II internalization is also blocked. Moreover, CD9 participates in MHC-II trafficking in mature MoDCs, regulating its endocytosis and recycling. Our results demonstrate that the tetraspanin CD9 specifically regulates antigenic presentation in MoDCs through the regulation of MHC-II intracellular trafficking.

scholarly journals Competition Model for Upregulation of the Major Histocompatibility Complex Class II-Associated Invariant Chain by Human Immunodeficiency Virus Type 1 Nef

2008 ◽  
Vol 82 (16) ◽  
pp. 7758-7767 ◽  
Author(s):  
Richard S. Mitchell ◽  
Rittik Chaudhuri ◽  
O. Wolf Lindwasser ◽  
Kristie A. Tanaka ◽  
David Lau ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Cell Surface ◽  
Invariant Chain ◽  
Complex Class ◽  
Mhc Ii ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Nef protein upregulates the expression of the invariant chain (Ii)/major histocompatibility complex class II (MHC-II) complex at the cell surface. This complex appears to reach the antigen-loading endosomal compartment at least in part via an indirect pathway in which it is internalized from the cell surface via the adaptor protein 2 (AP-2) complex. Here we provide evidence for a competition model to explain how Nef upregulates the expression of Ii at the cell surface. In this model, Nef and Ii compete for binding to AP-2. In support of this model, Nef decreased the rate of internalization of Ii from the cell surface. The AP-binding dileucine motif in Nef, ENTSLL165, was necessary and sufficient for the upregulation of Ii. In addition, two leucine-based AP-binding motifs in the Ii cytoplasmic tail, DDQRDLI8 and EQLPML17, were critical for the efficient upregulation of Ii by Nef. Experiments using Nef variants in which the native dileucine-based sorting motif was replaced with similar motifs from cellular transmembrane proteins allowed modulation of AP-binding specificity. Analysis of these variants suggested that the binding of Nef to AP-2 is sufficient to upregulate Ii at the plasma membrane. Finally, interference with the expression of AP-2 caused an upregulation of Ii at the plasma membrane, and this decreased the effect of Nef. These data indicate that Nef usurps AP-2 complexes to dysregulate Ii trafficking and potentially interfere with antigen presentation in the context of MHC-II.

scholarly journals Human Immunodeficiency Virus-1 Nef Expression Induces Intracellular Accumulation of Multivesicular Bodies and Major Histocompatibility Complex Class II Complexes: Potential Role of Phosphatidylinositol 3-Kinase

2003 ◽  
Vol 14 (12) ◽  
pp. 4857-4870 ◽  
Author(s):  
Pamela Stumptner-Cuvelette ◽  
Mabel Jouve ◽  
Julie Helft ◽  
Marc Dugast ◽  
Anne-Sophie Glouzman ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Cell Surface ◽  
Multivesicular Bodies ◽  
Complex Class ◽  
Phosphatidylinositol 3 Kinase ◽  
Mhc Ii ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus

Nef alters the cell surface expression of several immunoreceptors, which may contribute to viral escape. We show that Nef modifies major histocompatibility complex class II (MHC II) intracellular trafficking and thereby its function. In the presence of Nef, mature, peptide-loaded MHC II were down-modulated at the cell surface and accumulated intracellularly, whereas immature (invariant [Ii] chain-associated) MHC II expression at the plasma membrane was increased. Antibody internalization experiments and subcellular fractionation analyses showed that immature MHC II were internalized from the plasma membrane but had limited access to lysosomes, explaining the reduced Ii chain degradation. Immunoelectron microscopy revealed that Nef expression induced a marked accumulation of multivesicular bodies (MVBs) containing Nef, MHC II, and high amounts of Ii chain. The Nef-induced up-regulation of surface Ii chain was inhibited by LY294002 exposure, indicating the involvement of a phosphatidylinositol 3-kinase, whose products play a key role in MVB biogenesis. Together, our results indicate that Nef induces an increase of the number of MVBs where MHC II complexes accumulate. Given that human immunodeficiency virus recruits the MVB machinery for its assembly process, our data raise the possibility that Nef is involved in viral assembly through its effect on MVBs.

scholarly journals Ii Chain Controls the Transport of Major Histocompatibility Complex Class II Molecules to and from Lysosomes

1997 ◽  
Vol 137 (1) ◽  
pp. 51-65 ◽  
Author(s):  
Valérie Brachet ◽  
Graça Raposo ◽  
Sebastian Amigorena ◽  
Ira Mellman
Keyword(s):  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Cell Surface ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
Antigenic Peptides ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Or Efficiency ◽  
Histocompatibility Complex

Major histocompatibility complex class II molecules are synthesized as a nonameric complex consisting of three αβ dimers associated with a trimer of invariant (Ii) chains. After exiting the TGN, a targeting signal in the Ii chain cytoplasmic domain directs the complex to endosomes where Ii chain is proteolytically processed and removed, allowing class II molecules to bind antigenic peptides before reaching the cell surface. Ii chain dissociation and peptide binding are thought to occur in one or more postendosomal sites related either to endosomes (designated CIIV) or to lysosomes (designated MIIC). We now find that in addition to initially targeting αβ dimers to endosomes, Ii chain regulates the subsequent transport of class II molecules. Under normal conditions, murine A20 B cells transport all of their newly synthesized class II I-Ab αβ dimers to the plasma membrane with little if any reaching lysosomal compartments. Inhibition of Ii processing by the cysteine/serine protease inhibitor leupeptin, however, blocked transport to the cell surface and caused a dramatic but selective accumulation of I-Ab class II molecules in lysosomes. In leupeptin, I-Ab dimers formed stable complexes with a 10-kD NH2-terminal Ii chain fragment (Ii-p10), normally a transient intermediate in Ii chain processing. Upon removal of leupeptin, Ii-p10 was degraded and released, I-Ab dimers bound antigenic peptides, and the peptide-loaded dimers were transported slowly from lysosomes to the plasma membrane. Our results suggest that alterations in the rate or efficiency of Ii chain processing can alter the postendosomal sorting of class II molecules, resulting in the increased accumulation of αβ dimers in lysosome-like MIIC. Thus, simple differences in Ii chain processing may account for the highly variable amounts of class II found in lysosomal compartments of different cell types or at different developmental stages.

scholarly journals Role of Phagosomes and Major Histocompatibility Complex Class II (MHC-II) Compartment in MHC-II Antigen Processing of Mycobacterium tuberculosis in Human Macrophages

2006 ◽  
Vol 74 (3) ◽  
pp. 1621-1630 ◽  
Author(s):  
Martha Torres ◽  
Lakshmi Ramachandra ◽  
Roxana E. Rojas ◽  
Karen Bobadilla ◽  
Jeremy Thomas ◽  
...  
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Class Ii ◽  
Complex Class ◽  
Human Macrophages ◽  
Mhc Ii ◽  
Histocompatibility Complex ◽  
Class Ii Mhc

ABSTRACT Mycobacterium tuberculosis resides in phagosomes inside macrophages. In this study, we analyzed the kinetics and location of M. tuberculosis peptide-major histocompatibility complex class II (MHC-II) complexes in M. tuberculosis-infected human macrophages. M. tuberculosis peptide-MHC-II complexes were detected with polyclonal autologous M. tuberculosis-specific CD4+ T cells or F9A6 T hybridoma cells specific for M. tuberculosis antigen (Ag) 85B (96-111). Macrophages processed heat-killed M. tuberculosis more rapidly and efficiently than live M. tuberculosis. To determine where M. tuberculosis peptide-MHC-II complexes were formed intracellularly, macrophages incubated with heat-killed M. tuberculosis were homogenized, and subcellular compartments were separated on Percoll density gradients analyzed with T cells. In THP-1 cells, M. tuberculosis Ag 85B (96- 111)-DR1 complexes appeared initially in phagosomes, followed by MHC class II compartment (MIIC) and the plasma membrane fractions. In monocyte-derived macrophages, M. tuberculosis peptide-MHC-II complexes appeared only in MIIC fractions and subsequently on the plasma membrane. Although phagosomes from both cell types acquired lysosome-associated membrane protein 1 (LAMP-1) and MHC-II, THP-1 phagosomes that support formation of M. tuberculosis peptide-MHC-II complexes had increased levels of both LAMP-1 and MHC-II. Thus, M. tuberculosis phagosomes with high levels of MHC-II and LAMP-1 and MIIC both have the potential to form peptide-MHC-II complexes from M. tuberculosis antigens in human macrophages.

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