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Processing pathway for protease B of Saccharomyces cerevisiae
C M Moehle1, C K Dixon, E W Jones
1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213.
The Journal of Cell Biology
|February 1, 1989
Summary
This study elucidates the posttranslational pathway of vacuolar protease B (PrB) in yeast. Researchers used antibodies to track PrB through cellular compartments, revealing its glycosylation and processing steps.
Area of Science:
- Biochemistry
- Molecular Biology
- Yeast Genetics
Background:
- Vacuolar protease B (PrB) is a key enzyme in yeast.
- Understanding its biosynthesis is crucial for cellular function.
Purpose of the Study:
- To elucidate the posttranslational biosynthetic pathway of yeast vacuolar protease B.
- To characterize the processing and glycosylation steps involved.
Main Methods:
- Utilized antibodies against synthetic peptides and E. coli-derived PRB1 ORF protein.
- Tracked protease B through endoplasmic reticulum and Golgi complex using immunodetection.
- Analyzed molecular weight changes during processing.
Main Results:
- Identified preproprotease B (76 kD) as the unglycosylated precursor.
- Demonstrated sequential glycosylation and proteolytic processing in ER and Golgi.
- Characterized intermediate forms (39 kD, 40 kD, 37 kD) leading to mature 31-kD PrB.
- Mature PrB contains only non-Asn-linked carbohydrates.
Conclusions:
- The posttranslational pathway of yeast protease B involves extensive glycosylation and proteolytic cleavage.
- Protease A plays a role in processing proprotease B.
- Mature protease B undergoes significant modification, losing Asn-linked glycans.