Match each letter with the correct number. a. Growth hormone binding1. Dimerizat
ID: 206483 • Letter: M
Question
Match each letter with the correct number.
a. Growth hormone binding1. Dimerization results in cross-phosphorylation b. Growth hormone receptor 2. Activates Ras c. Receptor tyrosine kinase 3. Activates JAK d. Grb-2 e. Sos f. Ras g. IRS h. Phosphoinositide kinase 8. Promotes movement of glucose transporters to the cell membrane i. PIP3-activated kinase j. Akt 4. Adaptor protein in insulin signaling pathway 5. Activates Akt 6. Binds IRS and forms IP3 7. Causes receptor dimerization 9. Small G-protein 10. Binds receptor tyrosine kinase and SosExplanation / Answer
Most of the steps mentioned here belong to the PIP3/Akt signaling pathway. The growth hormone binding to the receptor results in the dimerization of receptor. The tyrosine kinase receptor is a cell surface receptor which has the high-affinity for various growth factors, cytokines, and hormones. It causes the dimerization of receptor and cross-phosphorylation of tyrosine residues in the intracellular domains. JAK (Janus kinase) is a type of cell surface receptor.
The PIP3/Akt signaling pathway consists of many activators, inhibitors, and secondary messengers. Because of many loops and branches, the pathway is very complex. The PIP3/Akt pathway starts with the activation of PIP3 kinase. This activation can be accomplished by three pathways. The two pathways begin with the activation of receptor belonging to the family of receptor tyrosine kinase by an extracellular growth factor. The binding of the factor leads to the dimerization of receptor monomers and the autophosphorylation of the monomers. Depending on the receptor different proteins may bind to a phosphorylated domain. The insulin receptor substrate (IRS) binds to the activated IGF receptor. The receptor bound IRS acts as an activation site for PIP3 activated kinase. In addition, PIP3 activated kinase may bind directly to a phosphorylated receptor tyrosine kinase. A third mechanism relies on the binding of a small G-protein, Ras. By binding to active GTP-bound Ras, PIP3 kinase is activated.
At the second level of the pathway, the secondary messenger PIP3 is formed. This leads to the activation of Akt (a serine-threonine kinase).
a. Growth hormone binding 7. Causes receptor dimerization b. Growth hormone receptor 3. Activates JAK c. Receptor tyrosine kinase 1. Dimerization results in cross-phosphorylation d. Grb-2 10. Binds receptor tyrosine kinase and Sos e. Sos 2. Activates Ras f. Ras 9. Small G-Protein g. IRS 4. Adaptor protein in insulin signaling pathway h. Phosphoinositide kinase 6. Binds IRS and forms IP3 i. PIP3-activated kinase 5. Activates Akt j. Akt 8. Promotes movement of glucose transporters to the cell membrane