Related Experiment Video
Updated: Aug 19, 2026
Quantification of Intracellular Growth Inside Macrophages is a Fast and Reliable Method for Assessing the Virulence of Leishmania Parasites
Published on: March 16, 2018
Biosynthesis of the major surface protease GP63 of Leishmania chagasi
Chaoqun Yao1, Kevin G Leidal, Andrew Brittingham
1Department of Internal Medicine, University of Iowa, SW34-GH, 200 Hawkins Dr., Iowa City, IA 52242, USA.
Abstract:
The protozoan Leishmania chagasi expresses a surface metalloprotease, GP63, whose abundance increases 14-fold as parasites grow from logarithmic to stationary phase. L. chagasi GP63 is encoded by three classes of MSP genes that are differentially expressed during parasite growth. Using metabolic labeling and immunoprecipitation, we found L. chagasi GP63 first appeared as a 66-kDa band that was replaced by a 63-kDa protein. This pattern also occurred in transfected L. donovani harboring detectable products of only one MSP gene, suggesting a precursor-product relationship. The half-life of GP63 increased from 29 h in logarithmic phase to >72 h in stationary phase promastigotes. GP63 loss from the cell was complemented by the appearance of a 63-kDa GP63 in extracellular medium in both membrane-associated and -free forms. Calculations suggested that the long and lengthening T(1/2) of cell-associated GP63 accounts in part for its progressive accumulation in the cell during promastigote growth. The current findings add yet another level of complexity to post-transcriptionally regulated expression of an abundant surface molecule in a trypanosomatid protozoan.
Insights
The surface metalloprotease GP63 in Leishmania chagasi increases significantly during parasite growth. Its accumulation is linked to a longer half-life and post-transcriptional regulation, adding complexity to surface molecule expression.
Area of Science:
- Parasitology
- Molecular Biology
- Biochemistry
Background:
- Leishmania chagasi protozoa express GP63, a surface metalloprotease.
- GP63 abundance increases 14-fold during parasite growth from logarithmic to stationary phases.
- GP63 is encoded by differentially expressed MSP genes.
Purpose of the Study:
- To investigate the expression dynamics and regulation of Leishmania chagasi GP63.
- To elucidate the precursor-product relationship and half-life of GP63.
- To understand the post-transcriptional regulation of abundant surface molecules in trypanosomatids.
Main Methods:
- Metabolic labeling and immunoprecipitation were used to track GP63.
- Analysis of GP63 in transfected Leishmania donovani.
- Determination of GP63 half-life in different growth phases.
Main Results:
- GP63 initially appeared as a 66-kDa precursor, replaced by a 63-kDa mature form.
- A precursor-product relationship was suggested by findings in transfected parasites.
- GP63 half-life increased from 29 h (logarithmic phase) to over 72 h (stationary phase).
- GP63 was released extracellularly in both membrane-associated and free forms.
Conclusions:
- The lengthening half-life of cell-associated GP63 contributes to its accumulation during promastigote growth.
- Post-transcriptional regulation significantly impacts the expression of abundant surface molecules in trypanosomatid protozoa.
- These findings add complexity to understanding surface molecule expression in Leishmania.
Related Concept Videos
01:30Leishmaniasis
01:21Antiprotozoal Agents