title: Receptor signaling lymphocyte-activation molecule family 1 (Slamf1) regulates membrane fusion and NADPH oxidase 2 (NOX2) activity by recruiting a Beclin-1/Vps34/ultraviolet radiation resistance-associated gene (UVRAG) complex.
abstract: Phagocytosis is a pivotal process by which macrophages eliminate microorganisms upon recognition by pathogen sensors. Surprisingly, the self-ligand cell surface receptor Slamf1 functions not only as a co-stimulatory molecule but also as a microbial sensor of several Gram-negative bacteria. Upon entering the phagosome of macrophages Slamf1 induces production of phosphatidylinositol 3-phosphate, which positively regulates the activity of the NOX2 enzyme and phagolysosomal maturation. Here, we report that in Escherichia coli-containing phagosomes of mouse macrophages, Slamf1 interacts with the class III PI3K Vps34 in a complex with Beclin-1 and UVRAG. Upon phagocytosis of bacteria the NOX2 activity was reduced in macrophages isolated from Beclin-1(+/-) mice compared with wild-type mice. This Slamf1/Beclin-1/Vps34/UVRAG protein complex is formed in intracellular membrane compartments as it is found without inducing phagocytosis in macrophages, human chronic lymphocytic leukemia cells, and transfectant HEK293 cells. Elimination of its cytoplasmic tail abolished the interaction of Slamf1 with the complex, but deletion or mutation of the two ITAM motifs did not. Both the BD and CCD domains of Beclin-1 were required for efficient binding to Slamf1. Because Slamf1 did not interact with Atg14L or Rubicon, which can also form a complex with Vps34 and Beclin-1, we conclude that Slamf1 recruits a subset of Vps34-associated proteins, which is involved in membrane fusion and NOX2 regulation.
authors.affiliation: Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA. cma@bidmc.harvard.edu
authors.forename: Chunyan
authors.initials: C
authors.lastname: Ma
authors.forename: Ninghai
authors.initials: N
authors.lastname: Wang
authors.forename: Cynthia
authors.initials: C
authors.lastname: Detre
authors.forename: Guoxing
authors.initials: G
authors.lastname: Wang
authors.forename: Michael
authors.initials: M
authors.lastname: O'Keeffe
authors.forename: Cox
authors.initials: C
authors.lastname: Terhorst
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics*; D000071186:Beclin-1; D002460:Cell Line; D058546:Class III Phosphatidylinositol 3-Kinases / Q000235:genetics*; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D018345:Mice, Knockout; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism*; D010588:Phagosomes / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C115010:Becn1 protein, mouse; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; C000604059:SLAMF1 protein, human; C000604062:Slamf1 protein, mouse; D025521:Tumor Suppressor Proteins; C408122:UVRAG protein, human; C512859:UVRAG protein, mouse; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; C056558:CYBB protein, human; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D058546:Class III Phosphatidylinositol 3-Kinases