Subcellular trafficking of growth hormone receptor and Jak2 under ligand exposure.
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.
Moulin
S
S
INSERM Unit 584, Hormone Targets, Faculty of Medicine Necker, Paris, France.
Bouzinba-Segard
H
H
Kelly
P A
PA
Finidori
J
J
D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002467:Cell Nucleus / Q000502:physiology; D006224:Cricetinae; D003593:Cytoplasm / Q000502:physiology; D004268:DNA-Binding Proteins / Q000276:immunology / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000502:physiology; D006056:Golgi Apparatus / Q000502:physiology; D019382:Human Growth Hormone / Q000235:genetics / Q000378:metabolism*; D053614:Janus Kinase 2; D018613:Microscopy, Confocal; D008894:Milk Proteins; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D011817:Rabbits; D011986:Receptors, Somatotropin / Q000235:genetics / Q000378:metabolism*; D050799:STAT5 Transcription Factor; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D014162:Transfection
D004268:DNA-Binding Proteins; D008894:Milk Proteins; D011518:Proto-Oncogene Proteins; D011986:Receptors, Somatotropin; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D019382:Human Growth Hormone; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2