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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.

SUBMITTER: Ma C

PROVIDER: S-EPMC3365751 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature

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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.

Ma Chunyan C Wang Ninghai N Detre Cynthia C Wang Guoxing G O'Keeffe Michael M Terhorst Cox C

The Journal of biological chemistry 20120409 22

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 repo ...[more]

PMID: 22493499

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Project description:Doxorubicin is a highly effective cancer treatment whose use is severely limited by dose-dependent cardiotoxicity. It is well established that doxorubicin increases reactive oxygen species (ROS) production. In this study, we investigated contributions to doxorubicin cardiotoxicity from Nox2 NADPH oxidase, an important ROS source in cardiac cells, which is known to modulate several key processes underlying the myocardial response to injury. Nox2-deficient mice (Nox2-/-) and wild-type (WT) controls were injected with doxorubicin (12 mg/kg) or vehicle and studied 8 weeks later. Echocardiography indicated that doxorubicin-induced contractile dysfunction was attenuated in Nox2-/- versus WT mice (fractional shortening: 29.5±1.4 versus 25.7±1.0%; P<0.05). Similarly, in vivo pressure-volume analysis revealed that systolic and diastolic function was preserved in doxorubicin-treated Nox2-/- versus WT mice (ejection fraction: 52.6±2.5 versus 28.5±2.3%, LVdP/dtmin: -8,379±416 versus -5,198±527 mmHg s(-1); end-diastolic pressure-volume relation: 0.051±0.009 versus 0.114±0.012; P<0.001). Furthermore, in response to doxorubicin, Nox2-/- mice exhibited less myocardial atrophy, cardiomyocyte apoptosis, and interstitial fibrosis, together with reduced increases in profibrotic gene expression (procollagen III?I, transforming growth factor-?3, and connective tissue growth factor) and matrix metalloproteinase-9 activity, versus WT controls. These alterations were associated with beneficial changes in NADPH oxidase activity, oxidative/nitrosative stress, and inflammatory cell infiltration. We found that adverse effects of doxorubicin were attenuated by acute or chronic treatment with the AT1 receptor antagonist losartan, which is commonly used to reduce blood pressure. Our findings suggest that ROS specifically derived from Nox2 NADPH oxidase make a substantial contribution to several key processes underlying development of cardiac contractile dysfunction and remodeling associated with doxorubicin chemotherapy.

Dataset Information

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.

Publications

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.

Similar Datasets

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