Glucosamine treatment-mediated O-GlcNAc modification of paxillin depends on adhesion state of rat insulinoma INS-1 cells.
- Kwak, Tae Kyoung; Kim, Hyeonjung; Jung, Oisun; Lee, Sin-Ae; Kang, Minkyung; Kim, Hyun Jeong; Park, Ji-Min; Kim, Sung-Hoon; Lee, Jung Weon
- Issue Date
- JOURNAL OF BIOLOGICAL CHEMISTRY Vol.285 No.46, pp. 36021-36031
- Protein-protein interactions and/or signaling activities at
focal adhesions, where integrin-mediated adhesion to extracellular
matrix occurs, are critical for the regulation of adhesiondependent
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 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.
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