The initiation of the activity of the inactive enzyme MAP kinase (MAPK).

Any process that activates or increases the frequency, rate or extent of type I hypersensitivity, a type of inflammatory response.

The regulated release of serotonin by a cell. Serotonin (5-hydroxytryptamine, or 5-HT) is a monoamine synthesised in serotonergic neurons in the central nervous system, enterochromaffin cells in the gastrointestinal tract and some immune system cells.

The regulated release of serotonin by a cell. Serotonin (5-hydroxytryptamine, or 5-HT) is a monoamine synthesised in serotonergic neurons in the central nervous system, enterochromaffin cells in the gastrointestinal tract and some immune system cells.

The cellular process in which a signal is conveyed to trigger a change in the activity or state of a cell. Signal transduction begins with reception of a signal (e.g. a ligand binding to a receptor or receptor activation by a stimulus such as light), or for signal transduction in the absence of ligand, signal-withdrawal or the activity of a constitutively active receptor. Signal transduction ends with regulation of a downstream cellular process, e.g. regulation of transcription or regulation of a metabolic process. Signal transduction covers signaling from receptors located on the surface of the cell and signaling via molecules located within the cell. For signaling between cells, signal transduction is restricted to events at and within the receiving cell.

A series of molecular signals initiated by activation of a receptor on the surface of a cell. The pathway begins with binding of an extracellular ligand to a cell surface receptor, or for receptors that signal in the absence of a ligand, by ligand-withdrawal or the activity of a constitutively active receptor. The pathway ends with regulation of a downstream cellular process, e.g. transcription.

A series of molecular signals initiated by activation of a receptor on the surface of a cell. The pathway begins with binding of an extracellular ligand to a cell surface receptor, or for receptors that signal in the absence of a ligand, by ligand-withdrawal or the activity of a constitutively active receptor. The pathway ends with regulation of a downstream cellular process, e.g. transcription.

The initiation of the activity of the inactive enzyme JUN kinase (JNK).

The chemical reactions and pathways resulting in the formation of leukotriene, a pharmacologically active substance derived from a polyunsaturated fatty acid, such as arachidonic acid.

Any process that activates or increases the frequency, rate or extent of mast cell degranulation.

Any process that activates or increases the frequency, rate or extent of the chemical reactions and pathways resulting in the formation of interleukin-3.

Any process that activates or increases the frequency, rate or extent of the chemical reactions and pathways resulting in the formation of granulocyte macrophage colony-stimulating factor.

Any process that activates or increases the frequency, rate or extent of the phosphorylation of peptidyl-tyrosine.

Any process that activates or increases the frequency, rate or extent of calcium-mediated signaling.

The component of the plasma membrane consisting of the gene products and protein complexes having at least some part of their peptide sequence embedded in the hydrophobic region of the membrane.

The leaflet of the plasma membrane that faces away from the cytoplasm and any proteins embedded or anchored in it or attached to its surface.

The external part of the cell wall and/or plasma membrane.

Any of the small (10-200 nm), heterogeneous, highly dynamic, sterol- and sphingolipid-enriched membrane domains that compartmentalize cellular processes. Small rafts can sometimes be stabilized to form larger platforms through protein-protein and protein-lipid interactions.