Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Journal of Neuroscience |
| Vol/bind | 26 |
| Udgave nummer | 2 |
| Sider (fra-til) | 632-43 |
| Antal sider | 11 |
| ISSN | 0270-6474 |
| DOI | |
| Status | Udgivet - 2006 |
| Udgivet eksternt | Ja |
Bibliografisk note
Keywords: Animals; Binding Sites; Calcium; Catecholamines; Cells, Cultured; Chromaffin Cells; Exocytosis; Liposomes; Mice; Mice, Knockout; Mutagenesis, Site-Directed; Nerve Tissue Proteins; Patch-Clamp Techniques; Phospholipids; Phosphorylation; Photolysis; Protein Binding; Protein Kinase C; Protein Processing, Post-Translational; Protein Structure, Tertiary; Recombinant Fusion Proteins; SNARE Proteins; Synaptotagmin I; Synaptotagmin II; Tetradecanoylphorbol Acetate; TransfectionAdgang til dokumentet
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Different effects on fast exocytosis induced by synaptotagmin 1 and 2 isoforms and abundance but not by phosphorylation. / Nagy, Gábor; Kim, Jun Hee; Pang, Zhiping P; Matti, Ulf; Rettig, Jens; Südhof, Thomas C; Sørensen, Jakob B.
I: Journal of Neuroscience, Bind 26, Nr. 2, 2006, s. 632-43.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - Different effects on fast exocytosis induced by synaptotagmin 1 and 2 isoforms and abundance but not by phosphorylation
AU - Nagy, Gábor
AU - Kim, Jun Hee
AU - Pang, Zhiping P
AU - Matti, Ulf
AU - Rettig, Jens
AU - Südhof, Thomas C
AU - Sørensen, Jakob B
N1 - Keywords: Animals; Binding Sites; Calcium; Catecholamines; Cells, Cultured; Chromaffin Cells; Exocytosis; Liposomes; Mice; Mice, Knockout; Mutagenesis, Site-Directed; Nerve Tissue Proteins; Patch-Clamp Techniques; Phospholipids; Phosphorylation; Photolysis; Protein Binding; Protein Kinase C; Protein Processing, Post-Translational; Protein Structure, Tertiary; Recombinant Fusion Proteins; SNARE Proteins; Synaptotagmin I; Synaptotagmin II; Tetradecanoylphorbol Acetate; Transfection
PY - 2006
Y1 - 2006
N2 - Synaptotagmins comprise a large protein family, of which synaptotagmin 1 (Syt1) is a Ca2+ sensor for fast exocytosis, and its close relative, synaptotagmin 2 (Syt2), is assumed to serve similar functions. Chromaffin cells express Syt1 but not Syt2. We compared secretion from chromaffin cells from Syt1 null mice overexpressing either Syt isoform. High time-resolution capacitance measurement showed that Syt1 null cells lack the exocytotic phase corresponding to the readily-releasable pool (RRP) of vesicles. Comparison with the amperometric signal confirmed that the missing phase of exocytosis consists of catecholamine-containing vesicles. Overexpression of Syt1 rescued the RRP and increased its size above wild-type values, whereas the size of the slowly releasable pool decreased, indicating that the availability of Syt1 regulates the relative size of the two releasable pools. The RRP was also rescued by Syt2 overexpression, but the kinetics of fusion was slightly slower than in cells expressing Syt1. Biochemical experiments showed that Syt2 has a slightly lower Ca2+ affinity for phospholipid binding than Syt1 because of a difference in the C2A domain. These data constitute evidence for the function of Syt1 and Syt2 as alternative, but not identical, calcium-sensors for RRP fusion. By overexpression of Syt1 mutated in the shared PKC/calcium/calmodulin-dependent kinase phosphorylation site, we show that phorbol esters act independently and upstream of Syt1 to regulate the size of the releasable pools. We conclude that exocytosis from mouse chromaffin cells can be modified by the differential expression of Syt isoforms and by Syt abundance but not by phosphorylation of Syt1.
AB - Synaptotagmins comprise a large protein family, of which synaptotagmin 1 (Syt1) is a Ca2+ sensor for fast exocytosis, and its close relative, synaptotagmin 2 (Syt2), is assumed to serve similar functions. Chromaffin cells express Syt1 but not Syt2. We compared secretion from chromaffin cells from Syt1 null mice overexpressing either Syt isoform. High time-resolution capacitance measurement showed that Syt1 null cells lack the exocytotic phase corresponding to the readily-releasable pool (RRP) of vesicles. Comparison with the amperometric signal confirmed that the missing phase of exocytosis consists of catecholamine-containing vesicles. Overexpression of Syt1 rescued the RRP and increased its size above wild-type values, whereas the size of the slowly releasable pool decreased, indicating that the availability of Syt1 regulates the relative size of the two releasable pools. The RRP was also rescued by Syt2 overexpression, but the kinetics of fusion was slightly slower than in cells expressing Syt1. Biochemical experiments showed that Syt2 has a slightly lower Ca2+ affinity for phospholipid binding than Syt1 because of a difference in the C2A domain. These data constitute evidence for the function of Syt1 and Syt2 as alternative, but not identical, calcium-sensors for RRP fusion. By overexpression of Syt1 mutated in the shared PKC/calcium/calmodulin-dependent kinase phosphorylation site, we show that phorbol esters act independently and upstream of Syt1 to regulate the size of the releasable pools. We conclude that exocytosis from mouse chromaffin cells can be modified by the differential expression of Syt isoforms and by Syt abundance but not by phosphorylation of Syt1.
U2 - 10.1523/JNEUROSCI.2589-05.2006
DO - 10.1523/JNEUROSCI.2589-05.2006
M3 - Journal article
C2 - 16407561
VL - 26
SP - 632
EP - 643
JO - The Journal of neuroscience : the official journal of the Society for Neuroscience
JF - The Journal of neuroscience : the official journal of the Society for Neuroscience
SN - 0270-6474
IS - 2
ER -