Mitogen Activated Protein Kinase 1 Interacting Protein 1 Like Protein (MAPK1IP1L)

This protein is unstable during the first meiotic division and accumulates only in MII, where it localizes to the spindle. It is a substrate of the Mos/.../MAPK pathway. The depletion of endogenous RNA coding for this protein by three different means (antisense RNA, double-stranded [ds] RNA, or morpholino oligonucleotides) induces severe spindle defects specific to MII oocytes. Overexpressing the protein from an RNA not targeted by the morpholino rescues spindle destabilization. However, dsRNA has no effect on the first two mitotic divisions.

A new MAPK substrate involved in maintaining spindle integrity during the CSF arrest of mouse oocytes, called MISS (for MAP kinase-interacting and spindle-stabilizing protein).