Fig. 1. Mad1 constructs. (A) Full length Homo sapiens Mad1 protein showing Mad1-Mad1 oligomerization domain, Mad2-binding domains, and RLK sequence essential for Bub1 and Bub3 interactions. (B) GST-Mad1F10, which lacks the first 320 amino acids of full length Mad1, but contains the Mad1-Mad1 oligomerization domain and the Mad2-binding domain. Notably, GST-Mad1F10 is also missing the last 162 amino acids, which includes the RLK Bub1 and Bub3-interaction sequence.