A maternally expressed membrane and cytoskeletal linker protein, which is essential for attachment of the centrosome to the male pronucleus. Promotes male and female pronucleus congression and subsequent fusion after fertilization. Congression is mediated by the sperm aster microtubules. Localized at both male and female pronuclear membranes during pronuclear congression and fusion. Colocalized with tubulin at the centrosome adjacent to the nuclear membrane. At prophase is localized at the centrosome on opposite sides of the zygotic nucleus and at the reforming nuclear membrane. At metaphase is juxtaposed with the centrosomes at the mitotic spindle poles. During chromosome segregation is localized with the chromatin. Undetectable at the centrosome at the onset of anaphase, but becomes again apparent by late mitosis. Expressed in embryos and early cleavage stages (at protein level). Maternally expressed. Expressed in early cleavage embryos, weakly at 4 hours post-fertilization (hpf) and undetected at 24 hpf. Defects in irag2 are a cause of pronuclear congression/fusion and chromosomal segregation abnormalities in the zygote named futile cycle (fue), a lethal recessive maternal-effect mutant. Mutant embryos undergo several cycles of anucleate cleavage and die. Belongs to the IRAG2 family.