FIGURE Calcium ions entering the cytosol from the extracellular medium activate regulated exocytosis in the proximal axon terminal of a pain receptor nerve cell.

UNFIGURE 15.1.

FIGURE ADP from damaged cells activates G q and hence phospholipase C  in platelets.

FIGURE The inositol trisphosphategated calcium channel is a calcium- selective channel in the membrane of the endoplasmic reticulum. An increase of cytosolic calcium concentration in platelets makes them sticky, initiating blood clotting.

FIGURE Scanning electron micrograph of a blood platelet on the damaged inner surface of a blood vessel. The platelet has activated, extending short processes called pseudopodia, and is ready to initiate blood clotting. Image by Mark Turmaine, Department of Cell and Developmental Biology, University College London. Reproduced by permission.

UNFIGURE 15.2.

FIGURE Calcium and cyclic AMP activate distinct but overlapping sets of target processes in skeletal muscle cells.

FIGURE Nerve cell mitochondria take up calcium from the cytosol. Experiment of William Coatesworth and Stephen Bolsover. First published in Cell Calcium 39, 217 (2006).

FIGURE Cyclic adenosine monophosphate, also called cyclic AMP or just cAMP.

FIGURE Scent-sensitive nerve cells send axons to the brain.

FIGURE Scent chemicals activate G s and hence adenylate cyclase in scent- sensitive nerve cells. cAMP then opens a nonselective cation channel in the plasma membrane.

FIGURE The PDGF receptor, like other growth factor receptors, activates the GTPase Ras and therefore the MAP kinase cascade.

FIGURE Amino acid residues adjacent to phosphotyrosine recruit specific subtypes of SH2 domain.

FIGURE The PDGF receptor, like other growth factor receptors, phosphorylates and hence activates phospholipase C .

FIGURE The insulin receptor phosphorylates and hence activates PI 3-kinase.

FIGURE PIP3 recruits protein kinase B (PKB) to the plasma membrane, where it is activated. Active PKB has many effects including exocytosis of vesicles containing glucose carriers. The action of PKB on the protein BAX will be described in Chapter 18.

FIGURE Signaling from type 1 cytokine receptors.

FIGURE Interactions of signaling pathways.