[Frontiers in Bioscience E4, 1898-1909, January 1, 2012]

Lysosomal protein trafficking in Giardia lamblia: common and distinct features

Maria C. Touz1, Maria R. Rivero1, Silvana L. Miras1,Juan S. Bonifacino2

1Instituto de Investigacion Medica Mercedes y Martin Ferreyra, INIMEC - CONICET, Friuli 2434, Cordoba, Argentina, 2Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA


1. Abstract
2. Introduction
3. Endosomal-lysosomal protein trafficking
3.1. Clathrin and adaptor proteins
3.2. Lysosomal proteins
3.3. Retromer complex and accessory proteins
3.3.1. Retromer complex
3.3.2. Dynamin
3.3.3. Rab GTPases and SNAREs
4. Summary and perspective
5. Acknowledgements
6. References


Giardia is a flagellated protozoan parasite that has to face different microenvironments during its life cycle in order to survive. All cells exchange materials with the extracellular medium through the reciprocal processes of endocytosis and secretion. Unlike more evolved cells, Giardia lacks a defined endosomal/lysosomal system, but instead possesses peripheral vacuoles that play roles in endocytosis, degradation, recycling, and secretion of proteins during growth and differentiation of the parasite. This review focuses on recent reports defining the role of different molecules involved in protein trafficking to the peripheral vacuoles, and discusses possible mechanisms of receptor recycling. Since Giardia is an early-branching protist, the study of this parasite may lead to a clearer understanding of the minimal machinery required for protein transport in eukaryotic cells.