Functional analysis of the exported type IV HSP40 protein PFL2550w in P. falciparum gametocytes

Wednesday, October 26, 2011 — Poster Session IV
2:00 p.m. – 4:00 p.m.	Natcher Conference Center	NIAID	INFECTDIS-8

Authors

• B Morahan
• C Strobel
• U Hasan
• S Eksi
• B Czesny
• K Williamson

Abstract

During Plasmodium falciparum infection, remodeling of the host red blood cell (RBC) is required for the parasite’s survival. Such modifications are mediated by the export of parasite proteins into the RBC that alter the architecture of the membrane and assist in the delivery of adhesins to the cell surface enabling the infected RBC to cytoadhere. Using microarray analysis, we identified several genes with encoded export sequences that were up-regulated during early gametocytogeneis. One of these, PFL2550w, encodes a type IV heat shock protein 40 (HSP40) that is expressed in gametocyte stages I-IV and is exported to the RBC cytoplasm. HSPs are traditionally induced under stressful conditions to maintain homeostasis but PFL2550w expression was not increased upon heat shock suggesting an alternate function. Targeted disruption of PFL2550w indicated the gene is not essential for gametocytogenesis in vitro and quantitative PCR showed there was not compensatory expression of the other type IV HSP40 genes in the absence of PFL2550w. Although P. falciparum HSP40 members are implicated in the trafficking of proteins to the RBC surface, removal of PFL2550w did not affect the targeting of other exported gametocyte proteins.

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