| 1. |
- Granseth, Björn, et al.
(författare)
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Clathrin-mediated endocytosis : the physiological mechanism of vesicle retrieval at hippocampal synapses
- 2007
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Ingår i: Journal of Physiology. - : Wiley. - 0022-3751 .- 1469-7793. ; 585:3, s. 681-686
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Forskningsöversikt (refereegranskat)abstract
- The maintenance of synaptic transmission requires that vesicles are recycled after releasing neurotransmitter. Several modes of retrieval have been proposed to operate at small synaptic terminals of central neurons, but the relative importance of these has been controversial. It is established that synaptic vesicles can collapse on fusion and the machinery for retrieving this membrane by clathrin-mediated endocytosis (CME) is enriched in the presynaptic terminal. But it has also been suggested that the majority of vesicles released by physiological stimulation are recycled by a second, faster mechanism called 'kiss-and-run', which operates in 1 s or less to retrieve a vesicle before it has collapsed. The most recent evidence argues against the occurrence of 'kiss-and-run' in hippocampal synapses. First, an improved fluorescent reporter of exocytosis (sypHy), indicates that only a slow mode of endocytosis (tau = 15 s) operates when vesicle fusion is triggered by a single nerve impulse or short burst. Second, this retrieval mechanism is blocked by overexpressing the C-terminal fragment of AP180 or by knockdown of clathrin using RNAi. Third, vesicle fusion is associated with the movement of clathrin and vesicle proteins out of the synapse into the neighbouring axon. These observations indicate that clathrin-mediated endocytosis is the major, if not exclusive, mechanism of retrieval in small hippocampal synapses.
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| 2. |
- Granseth, Björn, et al.
(författare)
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Clathrin-mediated endocytosis is the dominant mechanism of vesicle retrieval at hippocampal synapses
- 2006
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Ingår i: Neuron. - : Elsevier BV. - 0896-6273 .- 1097-4199. ; 51:6, s. 773-786
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Tidskriftsartikel (refereegranskat)abstract
- The maintenance of synaptic transmission requires that vesicles be recycled after releasing neurotransmitter. Several modes of retrieval have been proposed to operate at small synaptic terminals of central neurons, including a fast "kiss-and-run" mechanism that releases neurotransmitter through a fusion pore. Using an improved fluorescent reporter comprising pHluorin fused to synaptophysin, we find that only a slow mode of endocytosis (tau = 15 s) operates at hippocampal synapses when vesicle fusion is triggered by a single nerve impulse or short burst. This retrieval mechanism is blocked by overexpression of the C-terminal fragment of AP180 or by knockdown of clathrin using RNAi, and it is associated with the movement of clathrin and vesicle proteins out of the synapse. These results indicate that clathrin-mediated endocytosis is the major, if not exclusive, mechanism of vesicle retrieval after physiological stimuli.
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| 3. |
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| 4. |
- Rieke, Johanna Magdalena, et al.
(författare)
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SLC20A1Is Involved in Urinary Tract and Urorectal Development
- 2020
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Ingår i: Frontiers in Cell and Developmental Biology. - : FRONTIERS MEDIA SA. - 2296-634X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies in developingXenopusand zebrafish reported that the phosphate transporterslc20a1ais expressed in pronephric kidneys. The recent identification ofSLC20A1as a monoallelic candidate gene for cloacal exstrophy further suggests its involvement in the urinary tract and urorectal development. However, little is known of the functional role ofSLC20A1in urinary tract development. Here, we investigated this using morpholino oligonucleotide knockdown of the zebrafish orthologslc20a1a. This caused kidney cysts and malformations of the cloaca. Moreover, in morphants we demonstrated dysfunctional voiding and hindgut opening defects mimicking imperforate anus in human cloacal exstrophy. Furthermore, we performed immunohistochemistry of an unaffected 6-week-old human embryo and detectedSLC20A1in the urinary tract and the abdominal midline, structures implicated in the pathogenesis of cloacal exstrophy. Additionally, we resequencedSLC20A1in 690 individuals with bladder exstrophy-epispadias complex (BEEC) including 84 individuals with cloacal exstrophy. We identified two additional monoallelicde novovariants. One was identified in a case-parent trio with classic bladder exstrophy, and one additional novelde novovariant was detected in an affected mother who transmitted this variant to her affected son. To study the potential cellular impact ofSLC20A1variants, we expressed them in HEK293 cells. Here, phosphate transport was not compromised, suggesting that it is not a disease mechanism. However, there was a tendency for lower levels of cleaved caspase-3, perhaps implicating apoptosis pathways in the disease. Our results suggestSLC20A1is involved in urinary tract and urorectal development and implicateSLC20A1as a disease-gene for BEEC.
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| 5. |
- Royle, Stephen J, et al.
(författare)
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Imaging phluorin-based probes at hippocampal synapses
- 2008
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Ingår i: Membrane Trafficking. - Totowa, NJ : Humana Press. - 9781597452618 ; , s. 293-303
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Accurate measurement of synaptic vesicle exocytosis and endocytosis is crucial to understanding the molecular basis of synaptic transmission. The fusion of a pH-sensitive green fluorescent protein (pHluorin) to various synaptic vesicle proteins has allowed the study of synaptic vesicle recycling in real time. Two such probes, synaptopHluorin and sypHy, have been imaged at synapses of hippocampal neurons in culture. The combination of these reporters with techniques for molecular interference, such as RNAi allows for the study of molecules involved in synaptic vesicle recycling. Here the authors describe methods for the culture and transfection of hippocampal neurons, imaging of pHluorin-based probes at synapses and analysis of pHluorin signals down to the resolution of individual synaptic vesicles.
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| 6. |
- Zhang, Rong, et al.
(författare)
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ISL1 is a major susceptibility gene for classic bladder exstrophy and a regulator of urinary tract development
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Previously genome-wide association methods in patients with classic bladder exstrophy (CBE) found association with ISL1, a master control gene expressed in pericloacal mesenchyme. This study sought to further explore the genetics in a larger set of patients following-up on the most promising genomic regions previously reported. Genotypes of 12 markers obtained from 268 CBE patients of Australian, British, German Italian, Spanish and Swedish origin and 1,354 ethnically matched controls and from 92 CBE case-parent trios from North America were analysed. Only marker rs6874700 at the ISL1 locus showed association (p = 2.22 x 10(-08)). A meta-analysis of rs6874700 of our previous and present study showed a p value of 9.2 x 10(-19). Developmental biology models were used to clarify the location of ISL1 activity in the forming urinary tract. Genetic lineage analysis of Isl1-expressing cells by the lineage tracer mouse model showed Isl1-expressing cells in the urinary tract of mouse embryos at E10.5 and distributed in the bladder at E15.5. Expression of isl1 in zebrafish larvae staged 48 hpf was detected in a small region of the developing pronephros. Our study supports ISL1 as a major susceptibility gene for CBE and as a regulator of urinary tract development.
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