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 process in which a precursor cell type acquires characteristics of a more mature T-cell. A T cell is a type of lymphocyte whose definin characteristic is the expression of a T cell receptor complex.

Any process in which a protein is maintained in a specific location within, or in the membrane of, a cell, and is prevented from moving elsewhere.

The process in which T cells that express T cell receptors that are restricted by self MHC protein complexes and tolerant to self antigens are selected for further maturation.

Any process that activates or increases the frequency, rate or extent of protein kinase activity.

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

Reactions triggered in response to the presence of a Gram-negative bacterium that act to protect the cell or organism.

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

Any process that modulates the frequency, rate or extent of T cell activation.

Any process that activates or increases the frequency, rate or extent of T cell activation.

The component of the plasma membrane consisting of gene products and protein complexes that have some part that spans both leaflets of the membrane.

The volume enclosed by the membranes of the endoplasmic reticulum.

The lipid bilayer surrounding the endoplasmic reticulum.

The membrane surrounding a cell that separates the cell from its external environment. It consists of a phospholipid bilayer and associated proteins.

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.