The Ca2+ pump is activated by the protein calmodulin. Explain the significance of this observation.
How is calmodulin activated? A. by binding both calcium and potassium B. by binding Ca2+ when the cytosolic concentration is greater than 500 nM C. by binding to a positively charged helix on another protein D. by binding Ca2+ only when calcium channels are open, allowing Ca2+ efflux from the cell E. None of the answers is correct.
Why might a signaling pathway want to use activated calmodulin to induce the pathway instead of binding Ca2+ directly to the enzyme complex?
Calmodulin is found in smooth muscle cells and performs a similar function to troponin in striated muscle fibers. However, calmodulin not only gets activated by Ca2+ but also slows the release of Ca2+ from the sarcoplasmic reticulum. How might this difference relate to the different kinds of contractions smooth muscles do in comparison to striated muscles? A study of muscle fibers between chimpanzees and humans revealed that although muscle mass per body size is approximately equivalent, the ratio of red...
44. Diacylglycerol and calcium activate a. protein kinase A. b. protein kinase C. c. PI 3-kinase. d. Ca2+/calmodulin-dependent kinase.
1. Explain the signaling cascade downstream of GPCR: • How trimeric G-protein is activated and inactivated? • What do a and By subunits do after G-protein activation?
In the cAMP signal transduction pathway, a protein kinase is activated. What happens next G protein is activated. cAMP is converted to ATP. The protein kinase activates a cellular response. GDP is replaced by GTP. Adenylyl cyclase is activated.
19. Which of these molecules is activated by Akt? A) Ras b) JAK-2 c) IP3 d) GLUT-4 20. When acting as a second messenger, Ca+2 often binds to which protein? A) ceruloplasmin b) calmodulin c) Akt d) JAK-2
If Ca2+Ca2+ is often bound on the surface of a protein by carboxylic acid functional groups. If the pKa of a particular −COOH−COOH group is 4.4, would you predict Ca2+Ca2+ to be most tightly bound at pHpH 7, pHpH 4.4, or pHpH 3?
You are studying a particular kind of Ca2+ transport protein in a purified system (the protein is the only transporter in the membrane). You find that if you add ATP to the interior of the membrane system, there is no change in the Ca?* concentration outside the cell. However, if you add an excess of Ca2+ to the interior of the cell, then you see an increase in the Ca2+ concentration outside the cell. What kind of transporter do you...
Question 4 1 pts Which of the following is a target protein we have already talked about that is bound (and activated) by active Calmodulin? Keratin Myosin Light Chain Kinase ATP Synthase Phospholipase C Actin