Cell surface organization of stress-inducible proteins ULBP and MICA that stimulate human NK cells and T cells via NKG2D
2004 (English)In: Journal of Experimental Medicine, ISSN 0022-1007, E-ISSN 1540-9538, Vol. 199, no 7, 1005-1010 p.Article in journal (Refereed) Published
Cell surface proteins major histocompatibility complex (MHC) class I-related chain A (MICA) and UL16-binding proteins (ULBP) 1, 2, and 3 are up-regulated upon infection or tumor transformation and can activate human natural killer (NK) cells. Patches of cross-linked raft resident ganglioside GM1 colocalized with ULBP1, 2, 3, or MICA, but not CD45. Thus, ULBPs and MICA are expressed in lipid rafts at the cell surface. Western blotting revealed that glycosylphosphatidylinositol (GPI)-anchored ULBP3 but not transmembrane MICA, MHC class I protein, or transferrin receptor, accumulated in detergent-resistant membranes containing GM1. Thus, MICA may have a weaker association with lipid rafts than ULBP3, yet both proteins accumulate at an activating human N-K cell immune synapse. Target cell lipid rafts marked by green fluorescent protein-tagged GPI also accumulate with ULBP3 at some synapses. Electron microscopy reveals constitutive clusters of ULBP at the cell surface. Regarding a specific molecular basis for the organization of these proteins, ULBP1, 2, and 3 and MICA are lipid modified. ULBP1, 2, and 3 are GPI anchored, and we demonstrate here that MICA is S-acylated. Finally, expression of a truncated form of MICA that lacks the putative site for S-acylation and the cytoplasmic tall can be expressed at the cell surface, but is unable to activate NK cells.
Place, publisher, year, edition, pages
2004. Vol. 199, no 7, 1005-1010 p.
immunological synapse, natural killer cell, fluorescence imaging, lipid rafts, intercellular communication, mhc class-i, lipid rafts, membrane domains, receptor, immunoreceptor, activation, triggers, costimulation, cytotoxicity, recruitment
IdentifiersURN: urn:nbn:se:kth:diva-23320DOI: 10.1084/jem.20032194ISI: 000220761000012OAI: oai:DiVA.org:kth-23320DiVA: diva2:342018
QC 201005252010-08-102010-08-10Bibliographically approved