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Cysteine proteinase changes during macrocyst formation in Dictyostelium mucoroides
M J North1, D A Cotter, K J Franek
1Department of Biological and Molecular Sciences, School of Natural Sciences, University of Stirling, U.K.
Abstract:
Cysteine proteinases were detected in vegetative myxamoebae of Dictyostelium mucoroides DM7 using chromogenic substrates and by electrophoretic analysis (gelatin-SDS-PAGE) which revealed three enzymes, dmCP30, dmCP35 and dmCP46 (a minor form). During the initial stages of macrocyst formation the cysteine proteinaes were secreted and disappeared almost completely from the cells. High extracellular levels of activity towards N-benzoyl-L-prolyl-L-phenylalanyl-L-arginine 4-nitroanilide and of dmCP30 persisted throughout macrocyst development. Three new intracellular proteinases, dmCP31, dmCP36 and dmCP40, were produced as macrocysts formed but their activity was only detected by gelatin-SDS-PAGE. Their appearance was specific to the developmental pathway leading to macrocyst formation. This is the first direct evidence for the accumulation of cysteine proteinases during a developmental process in a cellular slime mould.
Insights
This study reveals cysteine proteinases accumulate during Dictyostelium mucoroides macrocyst formation. New intracellular enzymes appear specifically during this developmental process.
Area of Science:
- Cellular biology
- Biochemistry
- Developmental biology
Background:
- Cysteine proteinases play roles in cellular processes.
- Their function during Dictyostelium mucoroides macrocyst formation is not fully understood.
Purpose of the Study:
- To investigate the presence and activity of cysteine proteinases during macrocyst formation in Dictyostelium mucoroides.
- To characterize the specific cysteine proteinases involved in this developmental process.
Main Methods:
- Detection of cysteine proteinases using chromogenic substrates.
- Electrophoretic analysis, specifically gelatin-SDS-PAGE, for enzyme identification.
- Monitoring enzyme activity and localization during macrocyst development.
Main Results:
- Cysteine proteinases were detected in vegetative myxamoebae, with three identified enzymes: dmCP30, dmCP35, and dmCP46.
- During early macrocyst formation, these enzymes were secreted and largely disappeared from cells.
- High extracellular activity of specific substrates and dmCP30 persisted throughout macrocyst development.
- Three novel intracellular proteinases (dmCP31, dmCP36, dmCP40) were produced specifically during macrocyst formation.
Conclusions:
- This research provides the first direct evidence of cysteine proteinase accumulation during a cellular slime mold developmental process.
- The study highlights the dynamic regulation of cysteine proteinases during Dictyostelium mucoroides macrocyst development.