The Traffic Of Soluble Hydrolases Is Mediated By Vps10p-Like Receptor In Giardia lamblia

MIRAS S.L., RIVERO M.R., QUIROGA R., ZAMPONI N., FELIZIANI C., RÓPOLO A.S., TOUZ M.C. ; MIRAS S.L., RIVERO M.R., QUIROGA R., ZAMPONI N., FELIZIANI C., RÓPOLO A.S., TOUZ M.C. ; MIRAS S.L., RIVERO M.R., QUIROGA R., ZAMPONI N., FELIZIANI C., RÓPOLO A.S., TOUZ M.C. ; MIRAS S.L., RIVERO M.R., QUIROGA R., ZAMPONI N., FELIZIANI C., RÓPOLO A.S., TOUZ M.C.

Congreso; 47th Annual Meeting. Argentine Society for Biochemistry and Molecular Biology Research; 2011

The targeting of lysosomal enzymes to their final destination is directed by a series of protein and recognition signals. Although, Giardia lamblia lacks a recognized Golgi apparatus or a typical endosome/lysosome system, it might have a specific and conserved mechanism by means the soluble hydrolases are sorted. In this work, we describe the presence of a Vps10p -like receptor and its function in sorting of lysosomal enzymes. By bioinformatics and proteinase K assays allowed us to determine that the gVps10p receptor is a type I transmembrana protein with a WD40 motif in the luminal portion and a cytoplasmic tyrosine motif (YQII). Immunoblot assay showed a 60 kDa but also a 120 kDa band, possibly related with a dimerization. IFA and confocal microscopy of trophozoites expressing gVps10p-HA fusion protein, showed that it localize around the nuclei colocalizing with the endoplasmic reticulum marker BIP (Immunoglobulin Binding Protein). Co-expression of gVPS10p-HA and gAcPh-V5 fusion proteins showed colocalization around nuclei and in the lysosomal peripheral vacuoles. On other hand, gVps10p-YQII-HA fusion protein, lacking the cytoplasmic tyrosine motif, showed a different subcelular distribution possibly related with changes in protein trafficking. This work will contribute to understand how the endosomal/lysosomal pathway works in the early divergent parasite Giardia lamblia.