GSBS Student Publications

Title

Interaction of the growth hormone receptor with cytokine-induced Src homology domain 2 protein in rat adipocytes

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Physiology

Date

2-15-2003

Document Type

Article

Medical Subject Headings

Adipocytes; Animals; Carrier Proteins; Cell Line; Cells, Cultured; Cysteine Endopeptidases; Cytokines; *DNA-Binding Proteins; Gene Expression; Growth Hormone; Humans; Immunosorbent Techniques; *Intracellular Signaling Peptides and Proteins; Kidney; Kinetics; Male; Multienzyme Complexes; Phosphorylation; Phosphotyrosine; Proteasome Endopeptidase Complex; Proteins; RNA, Messenger; Rats; Receptors, Somatotropin; *Repressor Proteins; Suppressor of Cytokine Signaling Proteins; *Trans-Activators; *Transcription Factors; Transfection; src Homology Domains

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

GH stimulates the phosphorylation of tyrosine residues in the GH receptor (GHR), Janus kinase 2 (JAK2), and other signaling proteins in a transient manner that subsides within 1 h. To assess the possible roles of cytokine-induced Src homology domain 2 (SH2) (CIS/SOCS) proteins in these transient responses, we studied the expression and disposition of CIS/SOCS proteins in rat adipocytes, a physiological target of GH action. A tyrosine-phosphorylated protein that appears to be the GHR was coprecipitated from extracts of GH-treated adipocytes with alpha-CIS. In contrast, no tyrosine-phosphorylated adipocyte proteins were recovered after immunoprecipitation with alpha-SOCS3, although coprecipitation of GHR with SOCS3 was readily detected in extracts of 3T3-F442A fibroblasts. Interaction of GHR with CIS peaked between 2 and 10 min after adipocytes were treated with GH, when tyrosine phosphorylation of the GHR was maximal. By 60 min after GH, tyrosine phosphorylation of the GHR declined to very low levels, and its interaction with CIS was reduced correspondingly. Proteasome inhibitors prevented the decline in tyrosine-phosphorylated GHR and prolonged interaction of GHR and CIS for at least 1 h. These findings demonstrate the interaction of CIS with the GHR in vivo and suggest that CIS may enhance degradation of the receptor by a proteasomal pathway.

Rights and Permissions

Citation: Endocrinology. 2003 Mar;144(3):868-76.

Related Resources

Link to article in PubMed

Journal Title

Endocrinology

PubMed ID

12586763