Growth hormone activity in mitochondria depends on GH receptor Box 1 and involves caveolar pathway targeting.

Growth hormone (GH) binding to its receptor (GHR) initiates GH-dependent signal transduction and internalization pathways to generate the biological effects. The precise role and way of action of GH on mitochondrial function are not yet fully understood. We show here that GH can stimulate cellular oxygen consumption in CHO cells transfected with cDNA coding for the full-length GHR.

Nuclear translocation and retention of growth hormone.

We have previously demonstrated that GH is subject to rapid receptor-dependent nuclear translocation. Here, we examine the importance of ligand activation of the GH-receptor (GHR)-associated Janus kinase (JAK) 2 and receptor dimerization for hormone internalization and nuclear translocation by use of cells stably transfected with cDNA for the GHR. Staurosporine and herbimycin A treatment of cells did not affect the ability of GH to internalize but resulted in increased nuclear accumulation of hormone.