Giardia lamblia EB1 is a functional homolog of yeast Bim1p that binds to microtubules.
Giardia lamblia, with two nuclei and a distinct polarized morphology, is an interesting organism for investigating how distribution of its microtubule (MT) is controlled during its cell cycle. In this study, we identified the end-binding protein 1 (EB1) of G. lamblia, a well-known microtubule-associated protein that organizes MTs in eukaryotes. Immunofluorescence assays using recombinant EB1 (rEB1)-specific antibodies demonstrated EB1 localization in nuclear membrane as well as in some cytoskeletal structures such as axomenes and median bodies of trophozoites of G. lamblia. Complementation experiments using the BIM1 knock-out mutant of yeast, the yeast homolog of mammalian EB1, showed that giardial EB1 was able to carry out a homologous function in controlling MT dynamics. In addition, rEB1 of G. lamblia co-precipitated with MTs by an in vitro binding assay, thereby demonstrating that G. lamblia EB1 is a MT-associated protein. These results, taken together, suggest that G. lamblia EB1 is a functional homolog of eukaryotic EB1 and is likely to be a determinant for MT distribution.
Kim
Juri
J
Department of Environmental Medical Biology and Institute of Tropical Medicine, Post Brain Korea 21 Program, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
Sim
Seobo
S
Kim
Junwon
J
Song
Kiwon
K
Yong
Tai-Soon
TS
Park
Soon-Jung
SJ
D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005816:Genetic Complementation Test; D016829:Giardia lamblia / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D006801:Humans; D008868:Microtubule Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D009154:Mutation; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
C119683:BIM1 protein, S cerevisiae; D018797:Cell Cycle Proteins; C405804:EB1 microtubule binding proteins; D008868:Microtubule Proteins; D008869:Microtubule-Associated Proteins; D015800:Protozoan Proteins; D029701:Saccharomyces cerevisiae Proteins