The classV myosin MYO2 is required for polarized growth during budding of S. cerevisiae. The ts myo2-66 mutant loses its ability to target growth properly resulting in large unbudded cells. Surprisingly, this myosin defect can be partially suppressed by Smy1p, which by sequence appears to be a kinesin. This suggests a unique interaction between an actin based motor and a microtubule based motor, although there is no evidence that Smy1p operates as a microtubule based motor. To further investigate the function of Smy1p we are attempting to find interacting proteins, using both the two-hybrid system and a Smy1p affinity column. In our two-hybrid assay we used a slightly truncated SMY1 to screen a Gal4 activation domain library. From this screen, we have obtained and are characterizing several positives. Pairwise tests for interactions of Smy1p with itself, Myo2p, actin, and microtubules are also being performed. The Smy1p affinity column was made from a bacterially expressed fusion of Smy1p and maltose binding protein. Applying yeast lysate to the affinity column yielded a single 82kd band. Unexpectedly, this protein was determined to be the L-A coat protein of the yeast killer virus. We will test whether the virus might be using Smy1p to promote viral transmission and will also repeat the affinity column with a virus free strain.