| Title | Age-dependent Preferential Dense-core Vesicle Exocytosis in Neuroendocrine Cells Revealed by Newly Developed Monomeric Fluorescent Timer Protein. | | Author(s) | Tsuboi T, Kitaguchi T, Karasawa S, Fukuda M, Miyawaki A | | Institution | Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan; Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan; Life Function and Dynamics, ERATO, JST, Wako, Saitama 351-0198, Japan; Amalgaam Co., Ltd, Itabashi, Tokyo 173-0004, Japan; Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan. | | Source | Mol Biol Cell 2009 Nov 4. | | Abstract | Monitoring Editor: Akihiko Nakano 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, 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 fashions. Our results suggest that coordinate functions of the two effectors of Rab27A, rabphilin and Slp4-a, are required for regulated secretory pathway. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19889833 |
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