Growth requires high amounts of energy. When there is not enough food available, animals slow down their growth so they can preserve energy to stay alive.
In nutrient dependent growth control, nutrient sensors keep track of the cell's nutrient status, such as levels of essential amino acids. The nutrient sensors then control for example ribosomes, which link amino acids to create new proteins, which are needed in growing cells.
The cell's ability to synthesize proteins depends on the rate new ribosomes are produced. Ribosome biogenesis also requires a lot of energy, so it is highly controlled.
PWP1 was now found to be a critical link between nutrient sensing in the cells and ribosome biogenesis. While doing so, PWP1 acts as a regulator of nutrition dependent growth of animals.
"The growth regulator functions in the same way in human and in fruit fly Drosophila, where we originally discovered it,” describes Associate Professor Ville Hietakangas from the Institute of Biotechnology, University of Helsinki.
Ribosomes are created at a high rate in uncontrollably multiplying cancer cells.
"Through a collaboration with cancer biologists in the University of Turku, we found that PWP1 is highly expressed in human tumours. The more it was expressed, the more aggressive the tumour was. So, if we could control ribosome biogenesis, we might be able to inhibit the malignant growth of tumours," researcher Ying Liu from the research group of Ville Hietakangas says.
Liu Y, Mattila J, Ventelä S, Yadav L, Zhang W, Lamichane N, Sundström J, Kauko O, Grénman R, Varjosalo M, Westermarck J, Hietakangas V. PWP1 Mediates Nutrient-Dependent Growth Control through Nucleolar Regulation of Ribosomal Gene Expression. Dev Cell. 2017 Oct 23;43(2):240-252.e5. doi: 10.1016/j.devcel.2017.09.022.