Figure 2.

A proposed flow chart to aid researchers to identify and classify PE‐proteins and to formulate testable hypotheses. When interested in a PE gene or protein, a first step can be to verify that it is indeed a functional PE protein, by investigating presence of the defining characteristics (Start at the left top of the flow chart). A following step is to classify the PE‐protein based on its C‐terminal domains (or lack thereof) and genomic localization.