TbFRP, a novel FYVE-domain containing phosphoinositide-binding Ras-like GTPase from trypanosomes
| Autor: | Mark C. Field, Vincent O. Adung'a |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Trypanosoma
Endosome Immunology Endocytic cycle Molecular Sequence Data Trypanosoma brucei brucei Euglenozoa Small G Protein GTPase Biology Phosphoinositide Phosphatidylinositols Article GTP Phosphohydrolases 03 medical and health sciences Open Reading Frames Protein structure Animals Amino Acid Sequence Phylogeny 030304 developmental biology 0303 health sciences 030302 biochemistry & molecular biology General Medicine Translocon Endocytosis Cell biology Protein Structure Tertiary Vesicular transport protein Infectious Diseases Biochemistry FYVE domain Proteolysis Trypanosomatina Parasitology Rabbits Genome Protozoan Intracellular transport Signal Transduction |
| Zdroj: | Experimental Parasitology |
| ISSN: | 1090-2449 |
| Popis: | Graphical abstract Highlights ► TbFRP is a GTPase with a novel architecture (FYVE-GTPase). ► Orthologs of TbFRP are restricted to Euglenozoa. ► TbFRP is rapidly cleaved to release the GTPase domain. ► The TbFRP FYVE domain is functional in PIP3-binding. ► Expression levels of TbFRP are controlled in a cell density dependent manner. Ras-like small GTPases are regulatory proteins that control multiple aspects of cellular function, and are particularly prevalent in vesicular transport. A proportion of GTPase paralogs appear restricted to certain eukaryote lineages, suggesting roles specific to a restricted lineage, and hence potentially reflecting adaptation to individual lifestyles or ecological niche. Here we describe the role of a GTPase, TbFRP, a FYVE domain N-terminally fused to a Ras-like GTPase, originally identified in Trypanosoma brucei. As FYVE-domains specifically bind phosphoinositol 3-phosphate (PI3P), which associates with endosomes, we suggest that TbFRP may unite phosphoinositide and small G protein endosomal signaling in trypanosomatids. TbFRP orthologs are present throughout the Euglenazoa suggesting that FRP has functions throughout the group. We show that the FYVE domain of TbFRP is functional in PI3P-dependent membrane targeting and localizes at the endosomal region. Further, while TbFRP is apparently non-essential, knockdown and immunochemical evidence indicates that TbFRP is rapidly cleaved upon synthesis, releasing the GTPase and FYVE-domains. Finally, TbFRP expression at both mRNA and protein levels is cell density-dependent. Together, these data suggest that TbFRP is an endocytic GTPase with a highly unusual mechanism of action that involves proteolysis of the nascent protein and membrane targeting via PI3P. |
| Databáze: | OpenAIRE |
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