Biomaterial Database

Lipoarabinomannan-induced cell signaling involves ceramide and mitogen-activated protein kinase. 2002

Madhumita Sirkar, and Subrata Majumdar

Department of Microbiology, Bose Institute, Calcutta 700 054, India.

Lipoarabinomannan (LAM) is a major cell wall-associated lipoglycan, produced in large amounts (15 mg/g of bacteria) in different species of mycobacteria. Our laboratory has previously reported that LAM from Mycobacterium smegmatis exerts its cytotoxic activity via inhibition of protein kinase C, a key signaling molecule inside the mononuclear cells (S. Ghosh, S. Pal, S. Das, S. K. Dasgupta, and S. Majumdar, FEMS Immunol. Med. Microbiol. 21:181-188, 1998). In this study we report that LAM from Mycobacterium tuberculosis induces a signal transduction pathway in favor of survivability of the host cells via the generation of ceramide, a novel second messenger. The endogenous ceramide level in mononuclear cells was found to be enhanced during LAM treatment. The effects of LAM on protein tyrosine phosphorylation in human peripheral blood mononuclear cells were examined. LAM enhanced the tyrosine phosphorylation of p42 mitogen-activated protein kinase and phosphoinositol 3-kinase (PI3 kinase) and dephosphorylation of stress-activated protein kinase. LAM-induced phosphorylation of p42 (extracellular signal-regulated kinase 2) was further enhanced by wortmannin, a PI3 kinase inhibitor. To examine whether these effects are due to elevation of endogenous ceramide, we exposed the cells to cell-permeative C(2)-ceramide exogenously and studied the activities of different protein kinases. Fluorescence-activated cell sorter analysis and morphological studies showed that LAM induces cell survival. Therefore, these results suggest the ability of LAM to induce ceramide in the altered signaling pathway and help in cell survival.

UI	MeSH Term	Description	Entries
D008070	Lipopolysaccharides	Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)	Lipopolysaccharide,Lipoglycans
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D002518	Ceramides	Members of the class of neutral glycosphingolipids. They are the basic units of SPHINGOLIPIDS. They are sphingoids attached via their amino groups to a long chain fatty acyl group. They abnormally accumulate in FABRY DISEASE.	Ceramide
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000077191	Wortmannin	An androstadiene metabolite produced by the fungi PENICILLIUM funiculosum that inhibits PHOSPHATIDYLINOSITOL-3-KINASES and alloantigen-specific activation of T-LYMPHOCYTES in human tumor cell lines. It is widely used in CELL BIOLOGY research and has broad therapeutic potential.	MS 54,MS-54,MS54
D000730	Androstadienes	Derivatives of the steroid androstane having two double bonds at any site in any of the rings.
D048031	JNK Mitogen-Activated Protein Kinases	A subgroup of mitogen-activated protein kinases that activate TRANSCRIPTION FACTOR AP-1 via the phosphorylation of C-JUN PROTEINS. They are components of intracellular signaling pathways that regulate CELL PROLIFERATION; APOPTOSIS; and CELL DIFFERENTIATION.	jun N-Terminal Kinase,c-jun Amino-Terminal Kinase,c-jun N-Terminal Kinase,jun-NH2-Terminal Kinase,jun-NH2-Terminal Kinases,Amino-Terminal Kinase, c-jun,JNK Mitogen Activated Protein Kinases,Kinase, jun N-Terminal,N-Terminal Kinase, c-jun,N-Terminal Kinase, jun,c jun Amino Terminal Kinase,c jun N Terminal Kinase,jun N Terminal Kinase,jun NH2 Terminal Kinase,jun NH2 Terminal Kinases
D019869	Phosphatidylinositol 3-Kinases	Phosphotransferases that catalyzes the conversion of 1-phosphatidylinositol to 1-phosphatidylinositol 3-phosphate. Many members of this enzyme class are involved in RECEPTOR MEDIATED SIGNAL TRANSDUCTION and regulation of vesicular transport with the cell. Phosphatidylinositol 3-Kinases have been classified both according to their substrate specificity and their mode of action within the cell.	PI-3 Kinase,Phosphatidylinositol-3-OH Kinase,PtdIns 3-Kinase,PI 3-Kinase,PI-3K,PI3 Kinases,PI3-Kinase,Phosphoinositide 3 Kinases,Phosphoinositide 3-Hydroxykinase,PtdIns 3-Kinases,3-Hydroxykinase, Phosphoinositide,Kinase, PI-3,Kinase, Phosphatidylinositol-3-OH,Kinases, PI3,Kinases, Phosphoinositide 3,PI 3 Kinase,PI3 Kinase,Phosphatidylinositol 3 Kinases,Phosphatidylinositol 3 OH Kinase,Phosphoinositide 3 Hydroxykinase,PtdIns 3 Kinase,PtdIns 3 Kinases
D020928	Mitogen-Activated Protein Kinases	A superfamily of PROTEIN SERINE-THREONINE KINASES that are activated by diverse stimuli via protein kinase cascades. They are the final components of the cascades, activated by phosphorylation by MITOGEN-ACTIVATED PROTEIN KINASE KINASES, which in turn are activated by mitogen-activated protein kinase kinase kinases (MAP KINASE KINASE KINASES).	Mitogen Activated Protein Kinase,Mitogen-Activated Protein Kinase,Kinase, Mitogen-Activated Protein,Kinases, Mitogen-Activated Protein,Mitogen Activated Protein Kinases,Protein Kinase, Mitogen-Activated,Protein Kinases, Mitogen-Activated