Related Experiment Videos
Procathepsin L self-association as a mechanism for selective secretion
1Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, USA.
Traffic (Copenhagen, Denmark)
|February 24, 2001
Summary
Procathepsin L self-associates into aggregates, forming dense vesicles in mouse fibroblasts. These vesicles facilitate selective secretion of procathepsin L, independent of mannose phosphate receptors.
Area of Science:
- Cell Biology
- Proteomics
- Molecular Biology
Background:
- Procathepsin L is a lysosomal cysteine pro-protease.
- Its precise localization and secretion mechanism in fibroblasts remain unclear.
Purpose of the Study:
- To investigate the intracellular localization and potential self-association of procathepsin L in mouse fibroblasts.
- To elucidate the mechanism of procathepsin L secretion.
Main Methods:
- Sucrose gradient ultracentrifugation of microsomes.
- Immunogold labeling and electron microscopy.
- Yeast two-hybrid assays.
Main Results:
- Procathepsin L was enriched in dense vesicles distinct from known organelles.
- Procathepsin L associated with vesicle membranes at acidic pH.
- Self-association of procathepsin L was detected via yeast two-hybrid assays.
- Procathepsin L localized to dense cores in vesicles near the plasma membrane and in multivesicular bodies.
Conclusions:
- Procathepsin L self-association may initiate dense vesicle formation.
- These vesicles could mediate selective procathepsin L secretion independently of mannose 6-phosphate receptors.