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Titolo:
Proteasomes are involved in the constitutive degradation of growth hormonereceptors
Autore:
Takagi, K; Saito, Y; Sawada, J;
Indirizzi:
Natl Inst Hlth Sci, Div Biochem & Immunochem, Setagaya Ku, Tokyo 1588501, Japan Natl Inst Hlth Sci Tokyo Japan 1588501 Setagaya Ku, Tokyo 1588501, Japan
Titolo Testata:
BIOLOGICAL & PHARMACEUTICAL BULLETIN
fascicolo: 7, volume: 24, anno: 2001,
pagine: 744 - 748
SICI:
0918-6158(200107)24:7<744:PAIITC>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
LIGAND-INDUCED INTERNALIZATION; HUMAN IM-9 CELLS; DOWN-REGULATION; BINDING PROTEIN; UBIQUITIN; ENDOCYTOSIS; MECHANISM; PLASMA; ASSOCIATION; LYMPHOCYTES;
Keywords:
human growth hormone receptor; constitutive degradation; proteasome inhibitor; ubiquitin;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Sawada, J Natl Inst Hlth Sci, Div Biochem & Immunochem, Setagaya Ku, 1-18-1 Kamiyoga, Tokyo 1588501, Japan Natl Inst Hlth Sci 1-18-1 Kamiyoga Tokyo Japan 1588501 1, Japan
Citazione:
K. Takagi et al., "Proteasomes are involved in the constitutive degradation of growth hormonereceptors", BIOL PHAR B, 24(7), 2001, pp. 744-748

Abstract

In the mouse Ba/F3-hGHR cell line, which stably expresses human growth hormone receptors (hGHRs), the hGHRs were rapidly degraded in the absence of the ligand, Human growth hormone-binding protein (hGH-BP), a soluble form ofhGHR, was released from Ba/F3-hGHR cells, but the hGH-BP release was less than 1% of total hGHRs in the cells. Therefore, the hGH-BP release does notmarkedly contribute to hGHR degradation in Ba/F3-hGHR cells. The constitutive degradation of hGHRs was inhibited by the proteasome inhibitors MG-132 and clasto-lactacystin beta -lactone, or the vacuolar H+-ATPase inhibitor, bafilomycin A(1).hGH-enhanced degradation of hGHRs was also inhibited by MG-132, Moreover, MG-132 inhibited the internalization of hGHRsas assessed by I-125-hGH binding to the cell surfaces. Ubiquitinated hGHRs were detected in the cell lysate and increased by hGH-treatment, Furthermore, MG-132 accumulated the ubiquitinated hGHRs induced by hGH, However, the ratio of ubiquitinated hGHRs to un-ubiquitinated hGHRswas very small, even with treatment involving both hGH and MG-132. In the hGH-untreated cells, the ubiquitinated hGHRs were weakly detected. However,the ubiquitination of hGHR was not enhanced by MG-132 as a result of immunoblotting. Thus, the ubiquitination of hGHR is unlikely to be involved, at least in the constitutive degradation. Taken together, both the proteasome pathway and endosome/lysosome pathway are involved in the constitutive degradation of hGHRs, Our results also suggest that ubiquitination of the hGHR itself is unlikely to be the trigger of the proteasome-dependent degradation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 09:37:55