During oocyte maturation the eggs capability to release Ca²⁺ increases and becomes maximal at the time of fertilization (MII arrest). Sperm induces at metaphase of meisosis II (MII) Ca²⁺ oscillations for several hours, releasing the egg from its MII arrest. The mechanisms involved in this optimization process are not fully understood. The Ca²⁺ oscillations are mainly released from the intracellular Ca²⁺ stores by the type 1 inositol 1,4,5-trisphosphate receptor (IP₃R1). The IP₃R1 is a signal integrator protein of more than 2700 amino acids making it a possible target for multiple regulation mechanisms. It is also known that the sensitivity of the IP₃R1 increases during oocyte maturation and one of the possible mechanisms is through kinase-mediated phosphorylation. We previously found that the IP₃R1 becomes phosphorylated at an MPM-2 epitope during oocyte maturation and remains in this state till MII. This phosphorylation is regulated by the MAPK pathway but our results demonstrate that MAPK does not directly phosphorylate the IP₃R1 at an MPM-2 epitope. They however suggest that MAPK might indirectly regulate the MPM-2 phosphorylation by disturbing the co-localisation of IP₃R1 and its kinase. Moreover, because the activation profile of Polo Like Kinase 1(Plk1) is similar to the phosphorylation of the MPM-2 site of the IP₃R1 during maturation, we suggest a direct role for Plk1 in IP₃R1 MPM-2 phosphorylation.