Learn More
Melanoma is one of the most aggressive cancers, and its incidence is increasing. These tumors derive from the melanocyte lineage and remain incurable after metastasis. Here we report that SONIC HEDGEHOG (SHH)-GLI signaling is active in the matrix of human hair follicles, and that it is required for the normal proliferation of human melanocytes in culture.(More)
Human immunodeficiency virus-1 (HIV-1) is primarily transmitted sexually. Dendritic cells (DCs) in the subepithelium transmit HIV-1 to T cells through the C-type lectin DC-specific intercellular adhesion molecule (ICAM)-3-grabbing nonintegrin (DC-SIGN). However, the epithelial Langerhans cells (LCs) are the first DC subset to encounter HIV-1. It has(More)
Host cells impose a broad range of obstacles to the replication of retroviruses. Tetherin (also known as CD317, BST-2 or HM1.24) impedes viral release by retaining newly budded HIV-1 virions on the surface of cells. HIV-1 Vpu efficiently counteracts this restriction. Here, we show that HIV-1 Vpu induces the depletion of tetherin from cells. We demonstrate(More)
The Nef protein of primate lentiviruses downregulates the cell surface expression of CD4 through a two-step process. First, Nef connects the cytoplasmic tail of CD4 with adaptor protein complexes (AP), thereby inducing the formation of CD4-specific clathrin-coated pits that rapidly endocytose the viral receptor. Second, Nef targets internalized CD4(More)
The Nef protein of primate lentiviruses down-regulates the cell surface expression of CD4 and probably MHC I by connecting these receptors with the endocytic machinery. Here, we reveal that Nef interacts with the mu chains of adaptor complexes, key components of clathrin-coated pits. For human immunodeficiency virus type 2 (HIV-2) and simian(More)
The human and simian immunodeficiency viruses (HIV and SIV) downregulate the cell surface expression of CD4, their primary receptor, and of class I histocompatibility complex (MHC-I), a critical mediator of immune recognition. While the first of these effects seems important to preserve viral infectivity, the second likely promotes immune evasion. Three(More)
The Nef protein of primate lentiviruses triggers the accelerated endocytosis of CD4 and of class I major histocompatibility complex (MHC-I), thereby down-modulating the cell surface expression of these receptors. Nef acts as a connector between the CD4 cytoplasmic tail and intracellular sorting pathways both in the Golgi and at the plasma membrane,(More)
Major-histocompatibility-complex (MHC) proteins are used to display, on the surface of a cell, peptides derived from foreign material - such as a virus - that is infecting that cell. Cytotoxic T lymphocytes then recognize and kill the infected cell. The HIV-1 Nef protein downregulates the cell-surface expression of class I MHC proteins, and probably thereby(More)
Sézary syndrome (SzS) is an advanced form of cutaneous T-cell lymphoma characterized by peripheral blood involvement, impaired cell-mediated immunity, and T-helper 1 (TH1) cytokine production. To understand the mechanism of these defects, we studied the expression and function of CD40L in peripheral blood mononuclear cells (PBMCs) of patients with SzS. We(More)
HIV-1 cell-to-cell transmission confers a strong advantage as it increases efficiency of transfer up to 100-fold compared with a cell-free route. Mechanisms of HIV-1 cell-to-cell transmission are still unclear and can in part be explained by the presence of actin-containing cellular protrusions. Such protrusions have been shown to facilitate cell-to-cell(More)