26.3G 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 消当
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
26.3G proteins may activate or inhibit target proteins G protein Effector func ion Second messenger Example ofreceptor Stimulates adenylyl cydase ↑caMP B-adrenergic Stimulates adenylyl cydase ↑cAMP Odorant Inhi bit s adenylate cyclase ↓cAMP Som atostatin Opens k channels 个 Membrane potential Closes Ca channels N Mem brane potential m2 acetycholine t(transducin) Stimulates cGM P phosphodie sterase cGMP Rhodopsin Activates phospholipase CB 个nsP3.DAG m1 acet yicholine Figure 26. 10 Classes of G proteins are distinguished by their effectors and are activated y a variety of transmembrane receptors 消当
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 26.3G proteins may activate or inhibit target proteins GDP Receptor activates G proten R GTP replaces GDP L a subunit dissociates GTP Figure 26 11 Activation of Gs causes the a subunit to activate Effecto activation adenylate cyclase dy cyclase 消当 AMP聊
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 b retroviruses have names of the form v-onc 消当
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