Preliminary characterization of a new phospholipase C capable of cleaving GPI acylated in Tryponosoma brucei

• Grant number: 01/13756-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2002
• End date: December 31, 2003
• Field of knowledge: Biological Sciences - Biochemistry - Biochemistry of Microorganisms
• Principal Investigator: Maria Lucia Cardoso de Almeida
• Grantee: Carolina Borsoi Moraes
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Trypanosoma brucei is the parasite that causes sleep disease in Africa and is an excellent model for biosynthesis and metabolism of glycosylphosphatidylinositol (GPI) anchors. Blood forms of the parasite express a GPP-specific phospholipase C (GPl-PLC), capable of releasing its variant surface glycoprotein (VSG) since it is anchored by GPI. The shape of this parasite that multiplies in the vector, the tsetse fly, is called procyclic and also has its surface covered by a protein anchored by GPI, the procycline. The difference between GPIs of VSG and procycline is the fact that the latter is acylated in inositol, which gives GPI resistance to GPl-PLC cleavage. In view of this consideration, it was decided to investigate whether the insect forms would not possess a phospholipase C activity capable of cleaving atypical GPIs in the inositol. A preliminary test demonstrated the existence of such an activity and the objective of this project is therefore to characterize this new enzymatic activity which, in addition to being able to play an important role in this stage of the parasite life cycle, may have important practical applications. (AU)