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The budding yeast spindle pole body (SPB) not only organizes the astral and nuclear microtubules but is also associated with a number of cell-cycle regulators that control mitotic exit. Here, we describe that the core SPB component Nudlp is a key protein that functions in both processes. The astral microtubule organizing function of Nudlp is mediated by its interaction with the γ-tubulin complex binding protein Spc72p. This function of Nudlp is distinct from its role in cell-cycle control: Nudlp binds the spindle checkpoint control proteins Bfalp and Bub2p to the SPB, and is part of the mitotic exit network (MEN) in which it functions upstream of CDC15 but downstream of LTE1. In conditional lethal nudl-2 cells, the MEN component Temlp, a GTPase, is mislocalized, whereas the kinase Cdcl5p is still associated with the SPB. Thus, in nudl-2 cells the failure of Temlp to interact with Cdcl5p at the SPB probably prevents mitotic exit. [ABSTRACT FROM AUTHOR]