Question

The primary effect of inositol trisphosphate (IP3) during T-cell activation is to _____?

1) cause an increase in cytosolic calcium concentration
2) activate phospholipase C-gamma
3) activate a MAP kinase cascade
4) facilitate the differentiation of immature effector T cells
5) align the microtubule-organizing center toward the antigen-presenting cell

Answer 1

The primary effect of inositol trisphosphate (IP3) during T-cell activation is to cause an increase in cytosolic calcium concentration by binding to and opening calcium channels on the endoplasmic reticulum.

Step-by-step explanation:

The primary effect of inositol trisphosphate (IP3) during T-cell activation is to cause an increase in cytosolic calcium concentration. When IP3 is produced following the activation of phospholipase C, it diffuses into the cytoplasm and binds to ligand-gated calcium channels on the smooth endoplasmic reticulum. This binding causes the channels to open, releasing sequestered Ca2+ ions into the cytoplasm, where they act as a secondary messenger, which in turn activate numerous other enzymes and signaling pathways within the cell.