Cell Signaling II

Question 1

Discuss the role of diaceylglycerol in signal transduction

Answer 1

It can activate protein kinase C. The protein kinase C can then in turn phosphorylate various proteins.

Question 2

Describe the role of IP3 in signal transduction

Answer 2

IP3 has a role in releasing Ca2+ into the cytosol. Increasing its Ca2+ leads to the binding of Ca2+ by calmodulin and calmodulin binds to and helps activate a kinase.

Question 3

Indicate how Ca2+/calmodulin activates CaM-kinase II

Answer 3

The Ca2+-calmodulin complex binds to the inhibiting site on the CaM-Kinase II and moves it out of the way so that nothing else can bind to this area. The protein kinase is now partially active but it will only be fully active after it phosphorylates itself (auto-phosphorylation) also in the inhibiting domain in order to really ensure that that site is unavailable.

Question 4

Adrenergic Receptors Type alpha 1

Answer 4

The GPCR subtype is alpha 1a, alpha 1b, and alpha 1d. They bind to the Gq protein.

Question 5

Adrenergic Receptors Type alpha 2

Answer 5

The GPCR subtype is alpha 2a, alpha 2b, and alpha 2c. They bind to the Gi, Go protein.

Question 6

Adrenergic Receptors Type beta

Answer 6

The GPCR subtype is beta 1, beta 2, and bta 3. Beta 1 and beta 2 bind to the Gs protein while the beta 3 binds to the Gi, Go, and Gs protein.

Question 7

Nitric Oxide

Answer 7

It is first formed by nitric oxide synthetase and it binds to the soluble guanylyl cyclase at the heme which activates the formation of cGMP from GTP which activates protein kinase G- the signal transduction pathway of protein kinase G leads to muscle relaxation.