The activity of IP3 receptors is tightly regulated through multiple mechanisms. These include: - IP3 Binding: IP3 binding to its receptor is the primary activation mechanism. - Ca2+ Modulation: Ca2+ itself can modulate IP3 receptor activity, often in a biphasic manner, enhancing or inhibiting function depending on the concentration. - Phosphorylation: Various kinases can phosphorylate IP3 receptors, altering their sensitivity and activity. - Protein-Protein Interactions: IP3 receptors interact with other proteins such as calmodulin and FKBP12, which can modulate receptor function.
