Q13257

MAD2L1 (also designated MAD2) is a component of the mitotic spindle checkpoint. Cells with mutated MAD2 do not undergo mitotic arrest in response to incorrect spindle fiber assembly, which results in missegregation and eventual cell death. MAD2L1 is localized to unattached kinetochores during prometaphase and disassociates upon spindle fiber attachment, indicating that MAD2L1 regulates kinetochore binding to the spindle fibers. Human MAD2L1 has also been shown to associate with insulin receptor (IR), but not IGFIR, implicating MAD2L1 as a mediator for IR-specific signaling.