THE HUMAN PROTEIN ATLAS BLOG
Image of the week - Membrane by Aleksandra Shaishi
It's the end of the week, and that means another HPA image of the week! This week's image was brought to us by citizen scientists in Project Discovery, and specifically by Aleksandra Shaishi who found this image playing Project Discovery.
The protein labeled in Fig 1. is an image of the antibody HPA006539, which labels solute carrier family 2 (facilitated glucose transporter) (SLC2A) member 3 and member 14. This is what we call a "multi-targeting" antibody as it binds more than one protein. Multi-targeted proteins are usually highly similar (homologous) making them hard to distinguish using antibodies, but often also have similar functions as is the case here where the proteins are members of the same family. This staining is in CACO-2 cells, human epithelial colorectal adenocarcinoma.
As the name suggests, the SLC2A group of proteins are involved in transport of glucose, a type of sugar, across the cell membrane. This is why we see the staining in these cells is localized to the plasma membrane.
Glucose is a crucial source of energy for the cell and is converted into the basic unit of energy in cells, ATP though a process known as cellular respiration. This is an ongoing process in the cell which builds up and stores energy in the form of ATP which is then used for various cell processes such as mitosis (Gelfant S.). The cell-to-cell variation seen particularly as low expression in mitotic cells (upper right) is probably due to the fact that the cell is primarily using energy and not working on generating it during mitosis.
Because having a stable supply of glucose is so important for a cell, a number of diseases are associated with the SLC2A group of proteins including diabetes and Alzheimer's disease (Shah K. et al. 2012). Due to it's role in cell growth and division, elevated glycolysis (transport and processing of glucose) is seen in many cancers. As such, this pathway is suggested as possible target for treatment in said cancers (Gatenby R. A. & Gillies R. J. 2007).
We would like to again thank Aleksandra Shaishi and all the citizen scientists participating in Project Discovery for their contribution to science! We look forward to meeting you at EVE Fanfest today in Iceland. Tune in at 13:00 UTC April 22, 2016 for the live stream of our presentation!