Abstract: The spindle pole body -SPB- is a multiprotein complex that organizes microtubules in yeast- Due to its large size and association with the nuclear membrane, little is known about its detailed structure- In particular, although many SPB components and some of the interactions between them have been identified, the molecular details of how most of these interactions occur are not known- The prevalence of predicted coiled-coil regions in SPB proteins suggests that some interactions may occur via coiled coils- Here this hypothesis is supported by biochemical characterization of isolated coiled-coil peptides derived from SPB proteins- Formation of four strongly self-associating coiled-coil complexes from Spc29, Spc42, and Spc72 was demonstrated by circular dichroism -CD- spectroscopy and a fluorescence resonance energy transfer -FRET- assay- Many weaker self- and heteroassociations were also detected by CD, FRET, and-or cross-linking- The thermal stabilities of nine candidate homooligomers were assessed; six unfolded cooperatively with melting temperatures ranging from <11 to >50 degrees C- Solution studies established that coiled-coil peptides derived from Spc42 and Spc72 form parallel dimers, and this was confirmed for Spc42 by a high-resolution crystal structure- These data contribute to a growing body of knowledge that will ultimately provide a detailed model of the SPB structure-