《植物细胞解剖学》课程教学资源（PPT）07

Plasma membrane Inside of cell of cell G-protein-linked Signal-Receptor nnTP t Inpu transmembrane Network ntracllr gnal transduction Fig 7-1 Plant cell signal transduction processes

Fig.7-1 Plant cell signal transduction processes

Gravit Photosynthetic light Photomorphogenic light Humidity Figure 7-2 Temperature Herbivores Wind CO. CHa (ethyle Pathogens Figure 18.1 Parasites External signals that affect plant growth and devel- Soil microorganisms oil quality opment include many aspects of the plant's physical, Toxic minerals and other Water status chemical, and biological environments. Some exter- allopathic chemicals nal signals come from other plants. Apart from Mineral gravitropic signals, all other signals vary in intensity nutrients often from minute to minute

Figure 7-2

Extracellular C 尺 aceptOR s meric rotein ∠ Adenyly1 yanase me;an。 <1 Binding of hormone nTo 们 ational chango in receptor (SDP (2 Receptor binds to G protein GDP 罕E GDP bound to G protoin subunits。f protein dissociate CAo subunit binds to a activating synthes traMP: hormone dissect→te nds to GTP CAMP ++ PP: (s Hydrolysis of sTP to GDF Figure 7-3 dissociate f cyclase smst以 notIon of g protein thatcan be activated by a receptor

Figure 7-3

Figure 14 19 Structure of calmodulin (A) Calmodulin con- sists of two globular ends separated by a flexible a helix. H2N Each globular end has two calcium-binding sites.(B)When the calcium-calmodulin complex associates with a prote it literally wraps around it. (From Alberts et al. 1994) H2N 2nm H2N 0 Figure 7-5

Figure 7-5

Hormone Protein EXTRACELLULAR Receptor DAG kinase SPACE C Plasma membrane CYTOSOL GayA Protein Cellular (inactive) response G protein Protein Phosphor (active) Figure 14 18 Summary diagram of the Cellular events in the inositol-lipid signal trans- response duction pathway coupled to seven panning G protein-linked receptors The binding of hormone to its receptor triggers activation of the a subunit of IPR- sensitive Bound IP3 the heterotrimeric G protein, which Ca channel activates the effector enzyme phos pholipase C(PLC). PLC cleaves PIP, in Endoplasmic reticulum the membrane to yield IP, and DAG or vacuole IP, diffuses into the cytosol and binds to IPx- gated calcium channels on the ER or vacuolar membrane, causing the release of calcium into the cytosol from intracellular stores. The increase in cytosolic calcium concentration leads to a cellular response. DAG remains in the membrane and activates protein kinase C The activated protein kinase C then phosphorylates other proteins, leading to a cellular response. In ani- mal cells the inositol-lipid pathway may also be coupled to receptor tyro sine kinases (From Lodish et al. 1995.) Figure 7-6

Figure 7-6