An allele of Trypanosoma brucei cytoplasmic phosphoglycerate kinase is a mosaic of other alleles and genes

Alexander, Kenneth R.; Parail, Abraham C.; Parsons, Marilyn

doi:10.1016/0166-6851(90)90174-k

Cited by 11 publications

(1 citation statement)

References 9 publications

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“…However, of the nine glycosomal enzymes sequences that are known, T. brucei fructose biphosphate aldolase (Clayton, 1985), T. brucei triosephosphate isomerase (Swinkels et al, 1986), T. brucei phosphoenolpyruvate carboxykinase (Kueng et al, 1989;Parsons and Smith, 1989), as well as a minor glycosomal phosphoglycerate kinase encoded by the A gene of the T. brucei PGK gene cluster (Alexander et al, 1990), still do not contain an obvious C-terminal tripeptide sequence that might function in glycosomal import by our present findings. These proteins may rely on a somewhat different import mechanism.…”

Section: Simultaneous Expression Of Luciferase and Neo In T Brucei Bmentioning

confidence: 99%

In vivo import of firefly luciferase into the glycosomes of Trypanosoma brucei and mutational analysis of the C-terminal targeting signal.

Sommer

Cheng

Keller

et al. 1992

MBoC

147

107

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The compartmentalization of glycolytic enzymes into specialized organelles, the glycosomes, allows the bloodstream form of Trypanosoma brucei to rely solely on glycolysis for its energy production. The biogenesis of glycosomes in these parasites has been studied intensively as a potential target for chemotherapy. We have adapted the recently developed methods for stable transformation of T. brucei to the in vivo analysis of glycosomal protein import. Firefly luciferase, a peroxisomal protein in the lantern of the insect, was expressed in stable transformants of the procyclic form of T. brucei, where it was found to accumulate inside the glycosomes. Mutational analysis of the peroxisomal targeting signal serine-lysine-leucine (SKL) located at the C-terminus of luciferase showed that replacement of the serine residue (Serine548) with a small neutral amino acid (A, C, G, H, N, P, T) still resulted in an import efficiency of 50-100% of the wild-type luciferase. Lysine549 could be substituted with an amino acid capable of hydrogen bonding (H, M, N, Q, R, S), whereas the C-terminal leucine550 could be replaced with a subset of hydrophobic amino acids (I, M, Y). Thus, a peroxisome-like C-terminal SKL-dependent targeting mechanism may function in T. brucei to import luciferase into the glycosomes. However, a few significant differences exist between the glycosomal targeting signals identified here and the tripeptide sequences that direct proteins to mammalian or yeast peroxisomes.

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