Horm Metab Res 2003; 35(7): 396-401
DOI: 10.1055/s-2003-41619
Original Basic
© Georg Thieme Verlag Stuttgart · New York

Subcellular Trafficking of Growth Hormone Receptor and Jak2 under Ligand Exposure

S.  Moulin1 , H.  Bouzinba-Segard1 , P.  A.  Kelly1 , J.  Finidori1
  • 1INSERM Unit 584, Hormone Targets, Faculty of Medicine Necker, Paris, France
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Publikationsverlauf

Received 6 January 2003

Accepted after Revision 14 April 2003

Publikationsdatum:
21. August 2003 (online)

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Abstract

In CHO cells, growth hormone stimulation induces a rapid degradation of mature and precursor forms of its receptor, but does not affect Jak2 concentration. Confocal analysis of the receptor and of specific markers for subcellular localization shows that ligand exposure induced the disappearance of cell surface receptors, while some receptors seem to be sequestered in the endoplasmic reticulum (ER) and in the Golgi apparatus. Using a tagged version of Jak2 (HA-Jak2) and double immuno-fluorescence analysis with anti-HA and anti-Stat5 antibodies, we demonstrate that ligand stimulation induces Stat5 nuclear accumulation while Jak2 remains localized in the cytoplasm. Immunoblots of nuclear extracts confirm the Jak2 nuclear exclusion.