Identification of phenylalanine 346 in the rat growth hormone receptor as being critical for ligand-mediated internalization and down-regulation
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Identification of phenylalanine 346 in the rat growth hormone receptor as being critical for ligand-mediated internalization and down-regulation. / Allevato, G; Billestrup, N; Goujon, L; Galsgaard, E D; Norstedt, G; Postel-Vinay, M C; Kelly, P A; Nielsen, Jens Høiriis.
In: The Journal of Biological Chemistry, Vol. 270, No. 29, 21.07.1995, p. 17210-4.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Identification of phenylalanine 346 in the rat growth hormone receptor as being critical for ligand-mediated internalization and down-regulation
AU - Allevato, G
AU - Billestrup, N
AU - Goujon, L
AU - Galsgaard, E D
AU - Norstedt, G
AU - Postel-Vinay, M C
AU - Kelly, P A
AU - Nielsen, Jens Høiriis
PY - 1995/7/21
Y1 - 1995/7/21
N2 - The functional significance of growth hormone (GH) receptor (GHR) internalization is unknown; therefore, we have analyzed domains and individual amino acids in the cytoplasmic region of the rat GHR required for ligand-mediated receptor internalization, receptor down-regulation, and transcriptional signaling. When various mutated GHR cDNAs were transfected stably into Chinese hamster ovary cells or transiently into monkey kidney (COS-7) cells, internalization of the GHR was found to be dependent upon a domain located between amino acids 318 and 380. Mutational analysis of aromatic residues in this domain revealed that phenylalanine 346 is required for internalization. Receptor down-regulation in transiently transfected COS-7 cells was also dependent upon the phenylalanine 346 residue of the GHR, since no GH-induced down-regulation was observed in cells expressing the F346A GHR mutant. In contrast, the ability to stimulate transcription of the serine protease inhibitor 2.1 promoter by the GHR was not affected by the phenylalanine 346 to alanine mutation. These results demonstrate that phenylalanine 346 is essential for GHR internalization and down-regulation but not for transcriptional signaling, suggesting that ligand-mediated endocytosis is not a prerequisite for GH-induced gene transcription.
AB - The functional significance of growth hormone (GH) receptor (GHR) internalization is unknown; therefore, we have analyzed domains and individual amino acids in the cytoplasmic region of the rat GHR required for ligand-mediated receptor internalization, receptor down-regulation, and transcriptional signaling. When various mutated GHR cDNAs were transfected stably into Chinese hamster ovary cells or transiently into monkey kidney (COS-7) cells, internalization of the GHR was found to be dependent upon a domain located between amino acids 318 and 380. Mutational analysis of aromatic residues in this domain revealed that phenylalanine 346 is required for internalization. Receptor down-regulation in transiently transfected COS-7 cells was also dependent upon the phenylalanine 346 residue of the GHR, since no GH-induced down-regulation was observed in cells expressing the F346A GHR mutant. In contrast, the ability to stimulate transcription of the serine protease inhibitor 2.1 promoter by the GHR was not affected by the phenylalanine 346 to alanine mutation. These results demonstrate that phenylalanine 346 is essential for GHR internalization and down-regulation but not for transcriptional signaling, suggesting that ligand-mediated endocytosis is not a prerequisite for GH-induced gene transcription.
KW - Animals
KW - Cells, Cultured
KW - Down-Regulation
KW - Growth Hormone
KW - Ligands
KW - Phenylalanine
KW - Rats
KW - Receptors, Somatotropin
KW - Signal Transduction
KW - Transcription, Genetic
M3 - Journal article
C2 - 7615519
VL - 270
SP - 17210
EP - 17214
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 29
ER -
ID: 47973183