Abstract
Synapsin I is abundant in neural tissues. Its phosphorylation is thought to regulate synaptic vesicle exocytosis in the pre-synaptic terminal by mediating vesicle tethering to the cytoskeleton. Using anti-synapsin antibodies, we detected an 85 kDa protein in liver cells and identified it as synapsin I. Like brain synapsin I, non-neuronal synapsin I is phosphorylated in vitro by protein kinase A and yields identical 32P-peptide maps after limited proteolysis. We also detected synapsin I mRNA in liver by northern blot analysis. These results indicate that the expression of synapsin I is more widespread than previously thought. Immunofluorescence analysis of several non-neuronal cell lines localizes synapsin I to a vesicular compartment adjacent to trans-elements of the Golgi complex, which is also labeled with antibodies against myosin II; no sub-plasma membrane synapsin I is evident. We conclude that synapsin I is present in epithelial cells and is associated with a trans-Golgi network-derived compartment; this localization suggest that it plays a role in modulating post-TGN trafficking pathways.
Original language | English (US) |
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Pages (from-to) | 3695-3704 |
Number of pages | 10 |
Journal | Journal of cell science |
Volume | 114 |
Issue number | 20 |
State | Published - 2001 |
Externally published | Yes |
Keywords
- Epithelial cells
- Myosin II
- Synapsin I
- Trans-Golgi network
- Vesicular traffic
ASJC Scopus subject areas
- Cell Biology