Polycystic kidney disease (PKD), a condition in which clusters of cysts develop and accumulate on kidneys, affecting 600,000 Americans, urgently need to develop effective medical therapies. æGlycosylation of integrins have a crucial effect on multiple cell functions, such as cell migration and signaling transduction. In this poster, we describe the glycosylation change for ?3 integrin in PKD. We characterized the primary sequence and glycopeptides of ?3 integrin from pkd1 wild type (WT) and pkd1 knock-out (KO) cells by using HPLC coupled to mass spectrometry (MS). We have mapped more than 80 percent of amino acid sequence of ?3 integrin, which were immuno-precipitated by ?3 integrin antibody from mouse kidney cells. A single chain form of ?3 integrin was discovered for the first time. Glycopeptide characterization was performed by accurate mass measurement on a Fourier transform Mass spectrometry and MS/MS or MS/MS/MS fragmentation on an ion trap mass spectrometer. ææDifferent glycan patterns were observed in KO cells as comparison to WT cells. At N925 & N928 sites, larger and hybrid type glycans were found in WT cells but complex glycan types containing sialic acid were only displayed in KO cells. In addition, complex type glycans with sialic acids were also upregulated in KO cells at the N971 site. We make a hypothesis that the sialyltransferase genes are activated in KO cells. Therefore, we suggest that the sialytransferase can be considered as a potential novel therapeutic target for the treatment of PKD.