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An essential dimeric membrane protein of trypanosome glycosomes
Author(s) -
Maier Alexander,
Lorenz Patrick,
Voncken Frank,
Clayton Christine
Publication year - 2001
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2001.02333.x
Subject(s) - biology , membrane protein , computational biology , microbiology and biotechnology , membrane , biochemistry
Kinetoplastid parasites compartmentalize the first seven enzymes of glycolysis in a peroxisome‐like microbody, the glycosome. Genes encoding the most abundant protein of the glycosomal membrane, GIM5, have been cloned and the protein characterized. Two genes, GIM5A and GIM5B , encode 26 kDa proteins. Although many microbody membrane proteins are conserved in evolution, the only homologues of GIM5 in the available databases are from the closely related kinetoplastids Trypanosoma cruzi and Leishmania . The N‐ and C‐termini are conserved between the two genes, and between species, and are oriented towards the cytosol. They are separated by a short loop that is located between two transmembrane domains and shows almost no sequence conservation. This suggests that the N‐ and C‐terminal domains are more important for function. GIM5 forms dimers in vivo . Overexpression of GIM5B inhibits growth, whereas depletion of GIM5 to below 10% of wild‐type levels is very rapidly lethal. This novel organellar membrane protein is therefore essential for bloodstream trypanosome survival.