Phosphorylation and ubiquitination in Growth Hormone Receptor endocytosis and signalling

Abstract

In her thesis Joyce Putters has described how cells of the body regulate the sensitivity for growth hormone. This is important because growth hormone promotes muscle strength, fights infections, accelerates wound healing and accelerates recovery after bone fractures. In addition, children with delayed growth can be treated with growth hormone. Recently, the growth hormone receptor has also been implicated in cancer growth. Therefore, understanding how cells regulate the activity of growth hormone is very important. Joyce has identified two proteins that to a greater extend determine the growth hormone activity of cells. While one protein increases the number of receptors, diminishes the other protein this number. The unique finding is that the sheer number of these proteins determines how many growth hormone receptors are present at the cell surface and available for growth hormone in the blood. The studies in her thesis offer new possibilities to discover drugs that can be used to control the growth hormone sensitivity of cells. Increased sensitivity might replace growth hormone suppletion in children. On the other hand, decreased sensitivity might slow cancer growth, acromegaly and aging processes.