Fig. 8. A model for the function of Mug27 during FSM formation. During sporulation in S. pombe, the Mug27 complex localizes to the SPB as a complex that is partially distinct from the SIN. Unlike the SIN, which always localizes to the SPB, Mug27 also localizes to the extending FSM and regulates the normal formation of the FSM by phosphorylation of unknown targets.