Signal Transduction Pathways in Medicine

Signal Transduction Pathways in Medicine

• G-protein coupled receptors are embedded in the plasma membrane and have a seven transmembrane domain.
• G-protein coupled receptors are associated with a heterotrimeric G protein consisting of gamma, alpha, and beta subunits.
• When a signal binds to the receptor, the alpha subunit of the G protein undergoes a conformational change and converts GDP to GTP, becoming active.
• The active alpha subunit can either stimulate adenylyl cyclase (G sub s) or inhibit adenylyl cyclase (G sub i).
• Activation of adenylyl cyclase leads to the conversion of ATP to cAMP, which activates protein kinase A (PKA).
• Inhibition of adenylyl cyclase prevents the conversion of ATP to cAMP and the activation of PKA.
• The alpha subunit of the G protein can also work through a different system, stimulating phospholipase C (G sub q).
• Phospholipase C activates the conversion of PIP2 to IP3 and DAG.
• IP3 causes the release of calcium from the endoplasmic reticulum, while DAG activates protein kinase C (PKC).
• G-protein coupled receptors control the endocrine hormones FSH, LH, ACTH, TSH, CRH, HCG, ADH, MSH, PTH, calcitonin, GHRH, glucagon, and histamine.
• Receptor tyrosine kinases are the largest class of signal transductors and have inherent enzyme activity.
• Receptor tyrosine kinases undergo dimerization and cross-phosphorylation, leading to the activation of downstream kinases in the MAP kinase cascade.

Signal Transduction Pathways in Medicine

• G-protein coupled receptors are embedded in the plasma membrane and have a seven transmembrane domain.
• G-protein coupled receptors are associated with a heterotrimeric G protein consisting of gamma, alpha, and beta subunits.
• When a signal binds to the receptor, the alpha subunit of the G protein undergoes a conformational change and converts GDP to GTP, becoming active.
• The active alpha subunit can either stimulate adenylyl cyclase (G sub s) or inhibit adenylyl cyclase (G sub i).
• Activation of adenylyl cyclase leads to the conversion of ATP to cAMP, which activates protein kinase A (PKA).
• Inhibition of adenylyl cyclase prevents the conversion of ATP to cAMP and the activation of PKA.
• The alpha subunit of the G protein can also work through a different system, stimulating phospholipase C (G sub q).
• Phospholipase C activates the conversion of PIP2 to IP3 and DAG.
• IP3 causes the release of calcium from the endoplasmic reticulum, while DAG activates protein kinase C (PKC).
• G-protein coupled receptors control the endocrine hormones FSH, LH, ACTH, TSH, CRH, HCG, ADH, MSH, PTH, calcitonin, GHRH, glucagon, and histamine.
• Receptor tyrosine kinases are the largest class of signal transductors and have inherent enzyme activity.
• Receptor tyrosine kinases undergo dimerization and cross-phosphorylation, leading to the activation of downstream kinases in the MAP kinase cascade.