Fin1 is a kinetochore protein, predicted to contain two putative coiled-coil regions at its C terminus. It is present in a filamentous structure associated with the spindle and spindle pole in dividing cells during anaphase [1]. Fin1 is a substrate of S-phase cyclin-dependent kinase (CDK). It binds to PP1 creating the Fin1- PPI complex which is recruited onto kinetochores promoting spindle assembly checkpoint (SAC) dis-assembly during anaphase [2]. This is an important step in cell division since the kinetochore is the docking site for the spindle assembly checkpoint that monitors the defects in chromosome attachment and blocks anaphase onset [1]. Fin1 has two RXXS/T sequences: S377 (RVTS), S526 (RKVS) that can be phosphorylated. Upon phosphorylation, interactions with other proteins such as Bmh1 and Bmh2 is promoted. However, de-phosphorylation during anaphase promotes the kinetochore recruitment of Fin1-PP1 [2].

1: The Saccharomyces cerevisiae Fin1 protein forms cell cycle-specific filaments between spindle pole bodies. van Hemert MJ, Lamers GE, Klein DC, Oosterkamp TH, Steensma HY, van Heusden GP; Proc Natl Acad Sci U S A. 2002;99:5390-5393. PMID:11929974

2: Fin1-PP1 Helps Clear Spindle Assembly Checkpoint Protein Bub1 from Kinetochores in Anaphase. Bokros M, Gravenmier C, Jin F, Richmond D, Wang Y; Cell Rep. 2016;14:1074-1085. PMID:26832405