Profiling Technique: Protein Expression Analysis

Just as scientists use microarray analysis to build gene expression profiles, they can build protein expression profiles to determine which proteins are being made and functioning in a cell or tissue sample.

Why would a scientist want to do this? The simple answer is that it is the proteins encoded by genes - and not the genes themselves - that perform most of the work needed for proper cell function.

Even if a gene is turned on, there is no guarantee that the protein it encodes is being made, because protein production in a cell can be controlled independently from gene expression.

mRNA Doesn't Mean You Have Protein

After an mRNA molecule is made, there are still many steps that need to happen in order to produce a functional protein from its code. Often forces in the cell conspire to alter or even destroy the mRNA or protein along the way.

Protein expression analysis can answer biological questions

Protein expression analysis involves breaking open a cell or tissue sample, isolating proteins, separating them based on physical properties to generate a "map" of expressed proteins, and identifying proteins of interest.

Protein expression profiling can give researchers a definitive picture of the proteins present in a cell at any given time. Comparing this picture with a reference sample can provide insight into biological questions about disease and drug response, as well as help identify promising drug targets.

Supported by a Science Education Partnership Award (SEPA) [No. 1 R25 RR16291-01] from the National Center for Research Resources, a component of the National Institutes of Health, Department of Health and Human Services. The contents provided here are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.