3gmh
Crystal Structure of the Mad2 Dimer
Structural highlights
FunctionMD2L1_HUMAN Component of the spindle-assembly checkpoint that prevents the onset of anaphase until all chromosomes are properly aligned at the metaphase plate. Required for the execution of the mitotic checkpoint which monitors the process of kinetochore-spindle attachment and inhibits the activity of the anaphase promoting complex by sequestering CDC20 until all chromosomes are aligned at the metaphase plate.[1] [2] [3] Publication Abstract from PubMedThe spindle checkpoint senses unattached kinetochores during prometaphase and inhibits the anaphase-promoting complex or cyclosome (APC/C), thus ensuring accurate chromosome segregation. The checkpoint protein mitotic arrest deficient 2 (Mad2) is an unusual protein with multiple folded states. Mad2 adopts the closed conformation (C-Mad2) in a Mad1-Mad2 core complex. In mitosis, kinetochore-bound Mad1-C-Mad2 recruits latent, open Mad2 (O-Mad2) from the cytosol and converts it to an intermediate conformer (I-Mad2), which can then bind and inhibit the APC/C activator cell division cycle 20 (Cdc20) as C-Mad2. Here, we report the crystal structure and NMR analysis of I-Mad2 bound to C-Mad2. Although I-Mad2 retains the O-Mad2 fold in crystal and in solution, its core structural elements undergo discernible rigid-body movements and more closely resemble C-Mad2. Residues exhibiting methyl chemical shift changes in I-Mad2 form a contiguous, interior network that connects its C-Mad2-binding site to the conformationally malleable C-terminal region. Mutations of residues at the I-Mad2-C-Mad2 interface hinder I-Mad2 formation and impede the structural transition of Mad2. Our study provides insight into the conformational activation of Mad2 and establishes the basis of allosteric communication between two distal sites in Mad2. Structure of an intermediate conformer of the spindle checkpoint protein Mad2.,Hara M, Ozkan E, Sun H, Yu H, Luo X Proc Natl Acad Sci U S A. 2015 Aug 24. pii: 201512197. PMID:26305957[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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