Nuclear translocation and retention of growth hormone
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Nuclear translocation and retention of growth hormone. / Mertani, Hichem C; Raccurt, Mireille; Abbate, Aude; Kindblom, Jenny; Törnell, Jan; Billestrup, Nils; Usson, Yves; Morel, Gérard; Lobie, Peter E.
I: Endocrinology, Bind 144, Nr. 7, 07.2003, s. 3182-95.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Nuclear translocation and retention of growth hormone
AU - Mertani, Hichem C
AU - Raccurt, Mireille
AU - Abbate, Aude
AU - Kindblom, Jenny
AU - Törnell, Jan
AU - Billestrup, Nils
AU - Usson, Yves
AU - Morel, Gérard
AU - Lobie, Peter E
PY - 2003/7
Y1 - 2003/7
N2 - We have previously demonstrated that GH is subject to rapid receptor-dependent nuclear translocation. Here, we examine the importance of ligand activation of the GH-receptor (GHR)-associated Janus kinase (JAK) 2 and receptor dimerization for hormone internalization and nuclear translocation by use of cells stably transfected with cDNA for the GHR. Staurosporine and herbimycin A treatment of cells did not affect the ability of GH to internalize but resulted in increased nuclear accumulation of hormone. Similarly, receptor mutations, which prevent the association and activation of JAK2, did not affect the ability of the hormone to internalize or translocate to the nucleus but resulted in increased nuclear accumulation of GH. These results were observed both by nuclear isolation and confocal laser scanning microscopy. Staurosporine treatment of cells in which human GH (hGH) was targeted to the cytoplasm (removal of secretion sequence) or to the nucleus (addition of the nuclear localization sequence of SV40 large T antigen) resulted in preferential accumulation of hGH in the nucleus. We further investigated the requirement of receptor dimerization for GH nuclear translocation using the non-receptor-dimerizing hGH antagonist, hGH-G120R, conjugated to fluorescein isothiocyanate. Confocal laser scanning microscopy demonstrated efficient internalization of both hGH and hGH-G120R but lack of nuclear translocation of hGH-G120R. Thus, we conclude that activation of JAK2 kinase and the subsequent tyrosine phosphorylation is not required for nuclear translocation of GH but is pivotal for the removal of the hormone from the nucleus, and that GH translocates into the nucleus in a GHR dimerized-dependent fashion.
AB - We have previously demonstrated that GH is subject to rapid receptor-dependent nuclear translocation. Here, we examine the importance of ligand activation of the GH-receptor (GHR)-associated Janus kinase (JAK) 2 and receptor dimerization for hormone internalization and nuclear translocation by use of cells stably transfected with cDNA for the GHR. Staurosporine and herbimycin A treatment of cells did not affect the ability of GH to internalize but resulted in increased nuclear accumulation of hormone. Similarly, receptor mutations, which prevent the association and activation of JAK2, did not affect the ability of the hormone to internalize or translocate to the nucleus but resulted in increased nuclear accumulation of GH. These results were observed both by nuclear isolation and confocal laser scanning microscopy. Staurosporine treatment of cells in which human GH (hGH) was targeted to the cytoplasm (removal of secretion sequence) or to the nucleus (addition of the nuclear localization sequence of SV40 large T antigen) resulted in preferential accumulation of hGH in the nucleus. We further investigated the requirement of receptor dimerization for GH nuclear translocation using the non-receptor-dimerizing hGH antagonist, hGH-G120R, conjugated to fluorescein isothiocyanate. Confocal laser scanning microscopy demonstrated efficient internalization of both hGH and hGH-G120R but lack of nuclear translocation of hGH-G120R. Thus, we conclude that activation of JAK2 kinase and the subsequent tyrosine phosphorylation is not required for nuclear translocation of GH but is pivotal for the removal of the hormone from the nucleus, and that GH translocates into the nucleus in a GHR dimerized-dependent fashion.
KW - Active Transport, Cell Nucleus
KW - Amino Acid Sequence
KW - Animals
KW - CHO Cells
KW - Cell Nucleus
KW - Cricetinae
KW - Cytoplasm
KW - DNA, Complementary
KW - Dimerization
KW - Enzyme Inhibitors
KW - Enzyme-Linked Immunosorbent Assay
KW - Gene Deletion
KW - Growth Hormone
KW - Janus Kinase 2
KW - Ligands
KW - Microscopy, Confocal
KW - Molecular Sequence Data
KW - Mutagenesis
KW - Protein-Tyrosine Kinases
KW - Proto-Oncogene Proteins
KW - Rats
KW - Receptors, Cell Surface
KW - Receptors, Somatotropin
KW - Staurosporine
KW - Transfection
U2 - 10.1210/en.2002-221121
DO - 10.1210/en.2002-221121
M3 - Journal article
C2 - 12810575
VL - 144
SP - 3182
EP - 3195
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
SN - 0013-7227
IS - 7
ER -
ID: 132899894