Glucosamine treatment-mediated O-GlcNAc modification of paxillin depends on adhesion state of rat insulinoma INS-1 cells.
Protein-protein interactions and/or signaling activities at focal adhesions, where integrin-mediated adhesion to extracellular matrix occurs, are critical for the regulation of adhesion-dependent cellular functions. Although the phosphorylation and activities of focal adhesion molecules have been intensively studied, the effects of the O-GlcNAc modification of their Ser/Thr residues on cellular functions have been largely unexplored. We investigated the effects of O-GlcNAc modification on actin reorganization and morphology of rat insulinoma INS-1 cells after glucosamine (GlcN) treatment. We found that paxillin, a key adaptor molecule in focal adhesions, could be modified by O-GlcNAc in INS-1 cells treated with GlcN and in pancreatic islets from mice treated with streptozotocin. Ser-84/85 in human paxillin appeared to be modified by O-GlcNAc, which was inversely correlated to Ser-85 phosphorylation (Ser-83 in rat paxillin). Integrin-mediated adhesion signaling inhibited the GlcN treatment-enhanced O-GlcNAc modification of paxillin. Adherent INS-1 cells treated with GlcN showed restricted protrusions, whereas untreated cells showed active protrusions for multiple-elongated morphologies. Upon GlcN treatment, expression of a triple mutation (S83A/S84A/S85A) resulted in no further restriction of protrusions. Together these observations suggest that murine pancreatic β cells may have restricted actin organization upon GlcN treatment by virtue of the O-GlcNAc modification of paxillin, which can be antagonized by a persistent cell adhesion process.
Kwak
Tae Kyoung
TK
Cancer Research Institute, Department of Tumor Biology, School of Dentistry, Seoul National University, Seoul 110-799.
Kim
Hyeonjung
H
Jung
Oisun
O
Lee
Sin-Ae
SA
Kang
Minkyung
M
Kim
Hyun Jeong
HJ
Park
Ji-Min
JM
Kim
Sung-Hoon
SH
Lee
Jung Weon
JW
D000117:Acetylglucosamine / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000378:metabolism; D005944:Glucosamine / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D007340:Insulinoma / Q000378:metabolism / Q000473:pathology; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D007797:Laminin / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D008856:Microscopy, Fluorescence; D009154:Mutation; D051419:Paxillin / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D012694:Serine / Q000235:genetics / Q000378:metabolism; D013311:Streptozocin
D000199:Actins; D007797:Laminin; D051419:Paxillin; C121346:laminin 1; D012694:Serine; D013311:Streptozocin; D005944:Glucosamine; D000117:Acetylglucosamine