Calcium waves in membrane fusion hagolysosome fusion is a calcium dependent process. Now, Randall Worth and colleagues (University of Pennsylvania School of Medicine, Philadelphia, PA), and Howard Petty and colleagues (University of Michigan School of Medicine, Ann Arbor, MI) find that a three amino acid motif in the IgG receptor Fc RIIA causes a calcium wave traveling along the plasma membrane...

Calcium waves in membrane fusion hagolysosome fusion is a calcium dependent process. Now, Randall Worth and colleagues (University of Pennsylvania School of Medicine, Philadelphia, PA), and Howard Petty and colleagues (University of Michigan School of Medicine, Ann Arbor, MI) find that a three amino acid motif in the IgG receptor Fc RIIA causes a calcium wave traveling along the plasma membrane...

Ceramide, a product of agonist-stimulated sphingomyelinase activation, is known to be generated during the phagocytosis of antibody-coated erythrocytes by polymorphonuclear leukocytes. Agonist-stimulated formation of ceramide-1-phosphate is now shown to occur in 32PO4-labeled neutrophils. Ceramide-1-phosphate is formed by a calcium-dependent ceramide kinase, found predominately in the neutrophi...

Coxiella burnetii, the etiological agent of Q fever, is an obligate intracellular bacterium proliferating within the harsh environment of the phagolysosome. Mechanisms controlling trafficking to, and survival of pathogens within, the phagolysosome are unknown. Two distinct morphological variants have been implicated as playing a role in C. burnetii survival. The dormant small-cell variant (SCV)...

The human neutrophil is a crucial participant in acute inflammation. Appropriate immune response is dependent on rapid direction of phagocytic cells through the tissue, towards the inflammatory focus. Such movement is governed by chemoattractants, e.g., interleukin-8 (IL-8/CXCL-8). Circulating neutrophils are packed with granules that contain effector molecules used for different cell activitie...

Phagocytic cells of the innate immune system, such as macrophages and neutrophils, are a primary line of defense against microbial infections. Patients with defects in innate immunity, such as those with chronic granulomatous disease or neutropenia, are extremely sensitive to a variety of infections. When a phagocyte recognizes the presence of an invading cell, it engulfs the microbe with its m...

Listeriolysin O (LLO) mediates the evasion of Listeria monocytogenes from the phagolysosome into the cytoplasm of the host cell. The recognition of infected cells by CD4 T cells is thought to be limited by the evasion of bacteria from the phagolysosome and also by the direct LLO-mediated inhibition of CD4 T cell activation. To analyze the influence of these immunoevasive mechanisms on the antil...

Listeriolysin O (LLO) is the major factor implicated in the escape of Listeria monocytogenes from the phagolysosome. It is the only representative of cholesterol-dependent cytolysins that exhibits pH-dependent activity. Despite intense studies of LLO pH-dependence, this feature of the toxin still remains incompletely explained. Here we used fluorescence and CD spectroscopy to show that the stru...

Leishmania parasites replicate within the phagolysosome compartment of mammalian macrophages. Although Leishmania depend on sugars as a major carbon source during infections, the nutrient composition of the phagolysosome remains poorly described. To determine the origin of the sugar carbon source in macrophage phagolysosomes, we have generated a N-acetylglucosamine acetyltransferase (GNAT) defi...