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Evidence for glucose and sorbitol‐induced nuclear export of glucokinase regulatory protein in hepatocytes
Author(s) -
Mukhtar Mohammed,
Stubbs Mark,
Agius Loranne
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01580-x
Subject(s) - glucokinase , nuclear export signal , nuclear transport , microbiology and biotechnology , cytoplasm , biochemistry , cell nucleus , chemistry , biology , enzyme
Glucokinase is rapidly exported from the nucleus of hepatocytes in response to a rise in glucose or fructose 1‐P. We demonstrate using confocal microscopy and quantitative imaging that in contrast to previous findings, the regulatory protein of glucokinase (GKRP) also translocates from the nucleus during substrate‐induced translocation of glucokinase. However, the fractional decrease in nuclear GKRP is smaller than for glucokinase and is determined by the metabolic state and not by the distribution of glucokinase. Translocation of glucokinase and GKRP is not inhibited by leptomycin B, an inhibitor of exportin‐1 function. These findings highlight the importance of quantitative imaging for determining nuclear export of proteins and suggest that GKRP may have a role in nuclear export or import of glucokinase.