Characterization of RAB-like4, the first identified RAB-like protein from Trypanosoma cruzi with GTPase activity.
RAB proteins, which belong to the RAS superfamily, regulate exocytic and endocytic pathways of eukaryotic cells, controlling vesicle docking and fusion. Few RAB proteins have been identified in parasites. Molecular markers for cellular compartments are important to studies concerning about the protein traffic in Trypanosoma cruzi, the causal agent of Chagas disease. In this work, we describe the characterization of TcRABL4, the first RAB-like gene identified in T. cruzi (GenBank Accession No.: ), present as a single-copy gene. TcRABL4 contains all five consensus RAB motifs but lacks cysteine residues at the C terminus, which are essential to isoprenylation, an absolute prerequisite for membrane association of these proteins. TcRABL4 is a functional GTPase that is able to bind and hydrolyze GTP, and its gene is transcribed as a single 1.2 kb mRNA in epimastigotes. TcRABL4 appears to be differentially regulated in the three cell forms of the parasite, and the protein is not associated to membranes, unlike other RAB proteins. It is possible that TcRABL4 may be a member of a novel family of small GTPases.
Laboratório de Metabolismo Macromolecular Firmino Torres de Castro, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS, Cidade Universitária, Rio de Janeiro 21949-900, Brazil.
Fabiane Pereira
FP
Ramos
Júlia Rolão
JR
Araripe
Turán Péter
TP
Urményi
Rosane
R
Silva
Narcisa Leal
NL
Cunha e Silva
Carlos Frederico
CF
Leite Fontes
José Franco
JF
da Silveira
Edson
E
Rondinelli
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D017931:DNA Primers; D016054:DNA, Protozoan; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics; D020695:rab4 GTP-Binding Proteins / Q000378:metabolism*
D017931:DNA Primers; D016054:DNA, Protozoan; D011994:Recombinant Proteins; D020558:GTP Phosphohydrolases; D020695:rab4 GTP-Binding Proteins