AUTHOR=Bouwmeester Klaas , Meijer Harold. J.G. , Govers Francine TITLE=At the Frontier; RXLR Effectors Crossing the Phytophthora–Host Interface JOURNAL=Frontiers in Plant Science VOLUME=Volume 2 - 2011 YEAR=2011 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2011.00075 DOI=10.3389/fpls.2011.00075 ISSN=1664-462X ABSTRACT=Everywhere plants grow they can be affected by pathogenic organisms. To successfully infect their hosts, plant pathogens secrete effector proteins, many of which are translocated to the inside of the host cell where they disturb normal physiological processes and undermine proper functioning. The way by which effectors cross the frontier to reach the inside of the host cell varies among different classes of pathogens. For oomycete plant pathogens - like the potato late blight pathogen Phytophthora infestans - it has been shown that effector translocation to the host cell cytoplasm is dependent on a conserved amino acid motif that is present in the N-terminal part of effector proteins. This so-called RXLR motif has a strong resemblance with a host translocation motif found in effectors secreted by Plasmodium species. These malaria parasites, that reside inside specialized vacuoles in red blood cells, make use of a specific protein translocation complex to export effectors from the vacuole into the red blood cell. Whether or not also oomycete RXLR effectors require a translocation complex to cross the frontier is still under investigation. For one P. infestans RXLR effector named IPI-O we have found a potential host target that coul