Glucose triggers the SRR (Snf3-Rgt2/Rgt1, or Sensor-Receptor/Repressor) glucose sensing pathway, which induces expression of hexose transporters (HXT). Extracellular glucose binds to the Snf3 and Rgt2 glucose sensors, leading to Yck1/2-mediated phosphorylation of the Mth1 and Std1 corepressors, resulting in their degradation, which relieves repression of the HXT genes. Most signaling pathways are modulated by an interplay of protein kinases and phosphatases. To identify protein phosphatases involved in glucose sensing we tested catalytic and regulatory subunits of protein phosphatases for their ability to induce HXT1 expression when overexpressed. Over-expression of PTP1 (phosphotyrosine phosphatase) and PPS1 (protein phosphatase S phase; dual-specificity phosphatase) increased HXT1 expression in cells growing on glucose. A plausible target for a phosphatase in the glucose signaling pathway is Yck1/2, whose Casein kinase 1 orthlogs in mammals and S. pombe are inhibited by autophosphorylation and activated by protein phosphatases. Since our results suggest a role for Tyr dephosphorylation, we tested if Yck2 activity is regulated by phosphorylation/dephosphorylation at Tyrosine residues. Conserved Tyr resudues were mutated to Phe (dephosphorylated form) or Glu (phosphomimetic). Interestingly, Tyr76>Glu showed a significant decrease in activity. Our study suggests a role for Ptp1 in regulation of glucose sensing pathway.