Welcome to another HPA image of the week! This week we take a look at vesicles and another type of data present in the HPA.

The protein stained in Fig 1. is an image of RAB5C. This protein is found in vesicles and specifically, in lysosomes of the cell. This sample shows HeLa human cervical adenocarcinoma cells.

These cells are actually transgenic and made to express green fluorescent protein on the RAB5C protein (RAB5Cgfp). This is a method we use to check the validity of our antibodies. If the HPA antibody (green) binds to RAB5Cgfp (magenta), the two should be seen in the same location in the cell giving us increased confidence that the antibody is binding the protein it was designed to. (A more extensive discussion about our GFP validations can be found in this previous blog).

One way cells process materials from their surroundings is through a process called "endocytosis" (Doherty G. J. & McMahon H. T.). In this process, vesicles called endosomes budd off the plasma membrane, engulfing certain reagents from the extracellular space. One path for vesicular products in endocytosis is to fuse with the lysosome, a vesicle that degrades materials.

RAB5C protein is a member of the RAS subfamily which is responsible for cell signaling. As a result, this family of proteins is responsible for signaling cell growth and division and is often implicated in cancers (Tan Y.S. et al. 2014). In fact, members of this protein family are known as "oncogenes" whose dysregulation is capable of transforming a healthy cells into tumor cells.