Question

The enzyme Phosphokinase C (PKC) is activated via a signaling cascade that begins with the action of the enzyme Phospholipase C in a cell membrane. The following chemical entities are involved in this cascade: i) Ca2+ ii) IP3 iii) Diacylglycerol Which of these is/are directly involved in binding to PKC?

A. i)

B. ii)

C. iii)

D. i) and iii)

E. ii) and iii)

Answer 1

where as Ca2+ and IP3 are the enzyme phospholipase C in cell membrane

Explanition:

PLC cleaves the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP₂) into diacyl glycerol (DAG) and inositol 1,4,5-trisphosphate (IP₃). DAG remains bound to the membrane, and IP₃ is released as a soluble structure into the cytosol. IP₃ then diffuses through the cytosol to bind to IP₃ receptors, particularly calcium channels in the smooth endoplasmic reticulum (ER). This causes the cytosolic concentration of calcium to increase, causing a cascade of intracellular changes and activity. In addition, calcium and DAG together work to activate protein kinase C, which goes on to phosphorylate other molecules, leading to altered cellular activity. End-effects include taste, tumor promotion, etc