26.3 G proteins may activate or inhibit target proteins Second messengers are small molecules that are generated when a signal transduction pathway is activated.The classic second messenger is cyclic AMP,which is generated when adenylate cyclase is activated by a G protein (when the G protein itself was activated by a transmembrane receptor). Serpentine receptor has 7 transmembrane segments. Typically it activates a trimeric G protein. 情菜大兰
Second messengers are small molecules that are generated when a signal transduction pathway is activated. The classic second messenger is cyclic AMP, which is generated when adenylate cyclase is activated by a G protein (when the G protein itself was activated by a transmembrane receptor). Serpentine receptor has 7 transmembrane segments. Typically it activates a trimeric G protein. 26.3 G proteins may activate or inhibit target proteins
26.3 G proteins may activate or inhibit target proteins G protein Effector fundion Second messenger Example of receptor Stimulates adenylyl cydase 个cAMP B-adrenergic olf Stimulates adenylyl cydase 个CAMP Odorant Inhibits adenylate cyclase cAMP Som atostatin Opens K'channels 个M embrane potential Closes Ca2+channels ↓Mem brane potential m2 acetycholine t(transducin) Stimulates cGMP phosphodiesterase ↓cGMP Rhodopsin Activates phospholipase CB 个InsP3,DA,G m1 acetycholine Figure 26.10 Classes of G proteins are distinguished by their effectors and are activated by a variety of transmembrane receptors. 清苇大当
Figure 26.10 Classes of G proteins are distinguished by their effectors and are activated by a variety of transmembrane receptors. 26.3 G proteins may activate or inhibit target proteins
Receptor G protein Effector 26.3 G proteins may activate or inhibit target proteins Recepfor activates G proten GTP replaces GDP Figure 26.11 Activation of Gs o subunit dssociates causes the a subunit to activate Effecto activation adenylate cyclase. e线0 台肥cyclase 清菜大当
Figure 26.11 Activation of Gs causes the a subunit to activate adenylate cyclase. 26.3 G proteins may activate or inhibit target proteins
26.4 Protein tyrosine kinases induce phosphorylation cascades Oncogenes are genes whose products have the ability to transform eukaryotic cells so that they grow in a manner analogous to tumor cells.Oncogenes carried by retroviruses have names of the form v-onc. 清苇大当
Oncogenes are genes whose products have the ability to transform eukaryotic cells so that they grow in a manner analogous to tumor cells. Oncogenes carried by retroviruses have names of the form v-onc. 26.4 Protein tyrosine kinases induce phosphorylation cascades