MAD1 antibody [9B10]

MAD1L1 (also called mitotic spindle assembly checkpoint protein, MAD1A, MAD1-like 1 and HsMAD1) is a component of the spindle-assembly checkpoint that prevents the onset of anaphase until all chromosomes are properly aligned at the metaphase plate. MAD1L1 has a role in the correct positioning of the septum and is required for anchoring MAD2L1 to the nuclear periphery. MAD1L1 forms a homodimer and also heterodimerizes with MAD2L1 in order to form a tetrameric MAD1L1-MAD2L1 core complex. Perturbation of the original MAD1L1-MAD2L1 structure by the spindle checkpoint may decrease MAD2L1 affinity for MAD1L1. CDC20 can compete with MAD1L1 for MAD2L1 binding, until the attachment and/or tension dampen the checkpoint signal, preventing further release of MAD2L1 on to CDC20. MAD1L1 is also able to interact with the BUB1/BUB3 complex and the viral Tax protein. MAD1L1 is a nuclear protein that is seen to move from the beginning to the end of mitosis from a diffusely nuclear distribution to the centrosome, to the spindle midzone and finally to the midbody. Multiple isoforms may exist for this protein (MAD1L1 and MAD1L2). MAD1L1 is induced by TP53 and is phosphorylated by BUB1. MAD1L1 is hyperphosphorylated in late S through M phases or after mitotic spindle damage. Defects in MAD1L1 are involved in the development and/or progression of various types of cancer.