RNA binding protein that modulates mRNA stability; regulates genes involved in the cell cycle, sister chromatid cohesion, and the stress response; modulates the stability and translational efficiency of the CLN3 mRNA; colocalizes with P-bodies/stress granules where it may sequester specific mRNAs; regulates cell fate and the critical cell size required for passage through Start; Tpk1p-mediated phosphorylation inhibits Whi3p function, decreasing its interaction with CLN3 mRNA; regulates ploidy