Question

Which alteration would reduce the amount of Ca₂⁺ released from the ER to the cytosol?

1) Decreasing the concentration of IP3 in the cytosol
2) Increasing the concentration of IP3 in the cytosol
3) Increasing the concentration of Ca₂⁺ in the cytosol
4) Decreasing the concentration of Ca₂⁺ in the cytosol

Answer 1

Decreasing the concentration of IP3 in the cytosol (option 1), would reduce the amount of Ca2+ released from the ER to the cytosol because IP3 binding to ER receptors triggers Ca2+ release.

Hence, the correct option would be 1) Decreasing the concentration of IP3 in the cytosol.

Step-by-step explanation:

To reduce the amount of Ca2+ released from the endoplasmic reticulum (ER) to the cytosol, one would need to decrease the concentration of IP3 in the cytosol. IP3 interacts with receptors on the ER and triggers the release of Ca2+. Therefore, a reduction in IP3 would lead to a decrease in Ca2+ release from the ER into the cytosol, diminishing the signal cascade within the cell.