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Age-dependent Preferential Dense-Core Vesicle Exocytosis in Neuroendocrine Cells Revealed by Newly Developed Monomeric Fluorescent Timer Protein
- Source :
- Molecular Biology of the Cell
- Publication Year :
- 2010
-
Abstract
- Using a newly developed protein-based fluorescent timer, mK-GO, which changes color with a predictable time course, we show that Rab27A effectors, rabphilin and Slp4-a, regulate age-dependent exocytosis of secretory vesicles in PC12 cells, and suggest that coordinate functions of the effectors are required for regulated secretory pathway.<br />Although it is evident that only a few secretory vesicles accumulating in neuroendocrine cells are qualified to fuse with the plasma membrane and release their contents to the extracellular space, the molecular mechanisms that regulate their exocytosis are poorly understood. For example, it has been controversial whether secretory vesicles are exocytosed randomly or preferentially according to their age. Using a newly developed protein-based fluorescent timer, monomeric Kusabira Green Orange (mK-GO), which changes color with a predictable time course, here we show that small GTPase Rab27A effectors regulate age-dependent exocytosis of secretory vesicles in PC12 cells. When the vesicles were labeled with mK-GO–tagged neuropeptide Y or tissue-type plasminogen activator, punctate structures with green or red fluorescence were observed. Application of high [K+] stimulation induced exocytosis of new (green) fluorescent secretory vesicles but not of old (red) vesicles. Overexpression or depletion of rabphilin and synaptotagmin-like protein4-a (Slp4-a), which regulate exocytosis positively and negatively, respectively, disturbed the age-dependent exocytosis of the secretory vesicles in different manners. Our results suggest that coordinate functions of the two effectors of Rab27A, rabphilin and Slp4-a, are required for regulated secretory pathway.
- Subjects :
- endocrine system
Aging
Time Factors
Vesicle fusion
Vesicular Transport Proteins
Biology
Models, Biological
PC12 Cells
Exocytosis
Mice
Neuroendocrine Cells
Animals
Neuropeptide Y
Small GTPase
Gene Silencing
RNA, Small Interfering
Molecular Biology
Secretory Vesicles
Vesicle
Munc-18
Articles
Cell Biology
Secretory Vesicle
Rats
Cell biology
Luminescent Proteins
Spectrometry, Fluorescence
Secretory protein
Tissue Plasminogen Activator
Subjects
Details
- Language :
- English
- Volume :
- 21
- Issue :
- No. 1
- Database :
- OpenAIRE
- Journal :
- Molecular Biology of the Cell
- Accession number :
- edsair.doi.dedup.....84f168579225ee26d3b873713206fc94