Connections between the protein kinases that function within complex cell polarity networks are poorly understood. Rod-shaped fission yeast cells grow in a highly polarized manner, and genetic screens have identified many protein kinases required for polarized growth and cell shape. Kin1, the sole MARK/PAR-1 family kinase in fission yeast, regulates cell polarity and cytokinesis through unknown mechanisms. We performed a large-scale phosphoproteomics screen to identify and characterize Kin1 substrates in cells.