scholarly journals The Longin Domain Regulates the Steady-State Dynamics of Sec22 in Plasmodium falciparum

2009 ◽  
Vol 8 (9) ◽  
pp. 1330-1340 ◽  
Author(s):  
Lawrence Ayong ◽  
Avanthi Raghavan ◽  
Timothy G. Schneider ◽  
Theodore F. Taraschi ◽  
David A. Fidock ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Golgi Apparatus ◽  
Protein Targeting ◽  
Snare Protein ◽  
Membrane Structures ◽  
Attachment Protein ◽  
Receptor Proteins ◽  
Specific Distribution ◽  
Protein Receptor ◽  
Sensitive Factor

ABSTRACT The specificity of vesicle-mediated transport is largely regulated by the membrane-specific distribution of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins. However, the signals and machineries involved in SNARE protein targeting to the respective intracellular locations are not fully understood. We have identified a Sec22 ortholog in Plasmodium falciparum (PfSec22) that contains an atypical insertion of the Plasmodium export element within the N-terminal longin domain. This Sec22 protein partially associates with membrane structures in the parasitized erythrocytes when expressed under the control of the endogenous promoter element. Our studies indicate that the atypical longin domain contains signals that are required for both endoplasmic reticulum (ER)/Golgi apparatus recycling of PfSec22 and partial export beyond the ER/Golgi apparatus interface. ER exit of PfSec22 is regulated by motifs within the α3 segment of the longin domain, whereas the recycling and export signals require residues within the N-terminal hydrophobic segment. Our data suggest that the longin domain of PfSec22 exhibits major differences from the yeast and mammalian orthologs, perhaps indicative of a novel mechanism for Sec22 trafficking in malaria parasites.

scholarly journals Role of the transmembrane domain in SNARE protein mediated membrane fusion: peptide nucleic acid/peptide model systems

2016 ◽  
Vol 12 (9) ◽  
pp. 2770-2776 ◽  
Author(s):  
Jan-Dirk Wehland ◽  
Antonina S. Lygina ◽  
Pawan Kumar ◽  
Samit Guha ◽  
Barbara E. Hubrich ◽  
...  
Keyword(s):  
Peptide Nucleic Acid ◽  
Transmembrane Domain ◽  
Fusion Peptide ◽  
Model Systems ◽  
Snare Protein ◽  
Attachment Protein ◽  
Receptor Proteins ◽  
Protein Receptor ◽  
Sensitive Factor

Analogs of the Soluble NSF (N-ethylmaleimide-sensitive factor) Attachment Protein Receptor proteins (SNAREs) for mediation of vesicle fusion.

scholarly journals Endosomal and Phagosomal SNAREs

2018 ◽  
Vol 98 (3) ◽  
pp. 1465-1492 ◽  
Author(s):  
Ilse Dingjan ◽  
Peter T. A. Linders ◽  
Danielle R. J. Verboogen ◽  
Natalia H. Revelo ◽  
Martin ter Beest ◽  
...  
Keyword(s):  
Intracellular Transport ◽  
Snare Proteins ◽  
Intracellular Pathogens ◽  
Snare Protein ◽  
Attachment Protein ◽  
System A ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Organelle Communication ◽  
Factor Attachment Protein Receptor

The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.

scholarly journals Prefused lysosomes cluster on autophagosomes regulated by VAMP8

2021 ◽  
Vol 12 (10) ◽  
Author(s):  
Qixin Chen ◽  
Mingang Hao ◽  
Lei Wang ◽  
Linsen Li ◽  
Yang Chen ◽  
...  
Keyword(s):  
Potential Role ◽  
Autophagic Flux ◽  
Snare Protein ◽  
Attachment Protein ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Fusion Probability ◽  
Autophagosome Maturation ◽  
Factor Attachment Protein Receptor

AbstractLysosome–autophagosome fusion is critical to autophagosome maturation. Although several proteins that regulate this fusion process have been identified, the prefusion architecture and its regulation remain unclear. Herein, we show that upon stimulation, multiple lysosomes form clusters around individual autophagosomes, setting the stage for membrane fusion. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein on lysosomes—vesicle-associated membrane protein 8 (VAMP8)—plays an important role in forming this prefusion state of lysosomal clusters. To study the potential role of phosphorylation on spontaneous fusion, we investigated the effect of phosphorylation of C-terminal residues of VAMP8. Using a phosphorylation mimic, we observed a decrease of fusion in an ensemble lipid mixing assay and an increase of unfused lysosomes associated with autophagosomes. These results suggest that phosphorylation not only reduces spontaneous fusion for minimizing autophagic flux under normal conditions, but also preassembles multiple lysosomes to increase the fusion probability for resuming autophagy upon stimulation. VAMP8 phosphorylation may thus play an important role in chemotherapy drug resistance by influencing autophagosome maturation.

scholarly journals SNARE zippering

2016 ◽  
Vol 36 (3) ◽  
Author(s):  
Xiaochu Lou ◽  
Yeon-Kyun Shin
Keyword(s):  
Recent Progress ◽  
Snare Complex ◽  
Intracellular Membrane ◽  
Attachment Protein ◽  
Receptor Proteins ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Associated Proteins ◽  
Intracellular Membrane Fusion ◽  
Factor Attachment Protein Receptor

SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins are a highly conserved set of membrane-associated proteins that mediate intracellular membrane fusion. Cognate SNAREs from two separate membranes zipper to facilitate membrane apposition and fusion. Though the stable post-fusion conformation of SNARE complex has been extensively studied with biochemical and biophysical means, the pathway of SNARE zippering has been elusive. In this review, we describe some recent progress in understanding the pathway of SNARE zippering. We particularly focus on the half-zippered intermediate, which is most likely to serve as the main point of regulation by the auxiliary factors.

Stable gene silencing of synaptotagmin I in rat PC12 cells inhibits Ca2+-evoked release of catecholamine

2006 ◽  
Vol 291 (2) ◽  
pp. C270-C281 ◽  
Author(s):  
Johnnie M. Moore ◽  
Jason B. Papke ◽  
Anne L. Cahill ◽  
Amy B. Harkins
Keyword(s):  
Pc12 Cells ◽  
Catecholamine Release ◽  
Stable Gene ◽  
Attachment Protein ◽  
Hairpin Rna ◽  
Receptor Proteins ◽  
Synaptotagmin I ◽  
Shrna Vector ◽  
Protein Receptor ◽  
Sensitive Factor

Synaptotagmin (syt) I is a Ca2+-binding protein that is well accepted as a major sensor for Ca2+-regulated release of transmitter. However, controversy remains as to whether syt I is the only protein that can function in this role and whether the remaining syt family members also function as Ca2+ sensors. In this study, we generated a PC12 cell line that continuously expresses a short hairpin RNA (shRNA) to silence expression of syt I by RNA interference. Immunoblot and immunocytochemistry experiments demonstrate that expression of syt I was specifically silenced in cells that stably integrate the shRNA-syt I compared with control cells stably transfected with the empty shRNA vector. The other predominantly expressed syt isoform, syt IX, was not affected, nor was the expression of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins when syt I levels were knocked down. Resting Ca2+ and stimulated Ca2+ influx imaged with fura-2 were not altered in syt I knockdown cells. However, evoked release of catecholamine detected by carbon fiber amperometry and HPLC was significantly reduced, although not abolished. Human syt I rescued the release events in the syt I knockdown cells. The reduction of stimulated catecholamine release in the syt I knockdown cells strongly suggests that although syt I is clearly involved in catecholamine release, it is not the only protein to regulate stimulated release in PC12 cells, and another protein likely has a role as a Ca2+ sensor for regulated release of transmitter.

scholarly journals Autophagosomal YKT6 is required for fusion with lysosomes independently of syntaxin 17

2018 ◽  
Vol 217 (8) ◽  
pp. 2633-2645 ◽  
Author(s):  
Takahide Matsui ◽  
Peidu Jiang ◽  
Saori Nakano ◽  
Yuriko Sakamaki ◽  
Hayashi Yamamoto ◽  
...  
Keyword(s):  
Hela Cells ◽  
Snare Complex ◽  
Snare Protein ◽  
Wild Type ◽  
Attachment Protein ◽  
Additional Mechanism ◽  
Protein Receptor ◽  
Evolutionarily Conserved ◽  
Sensitive Factor ◽  
Factor Attachment Protein Receptor

Macroautophagy is an evolutionarily conserved catabolic mechanism that delivers intracellular constituents to lysosomes using autophagosomes. To achieve degradation, lysosomes must fuse with closed autophagosomes. We previously reported that the soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) protein syntaxin (STX) 17 translocates to autophagosomes to mediate fusion with lysosomes. In this study, we report an additional mechanism. We found that autophagosome–lysosome fusion is retained to some extent even in STX17 knockout (KO) HeLa cells. By screening other human SNAREs, we identified YKT6 as a novel autophagosomal SNARE protein. Depletion of YKT6 inhibited autophagosome–lysosome fusion partially in wild-type and completely in STX17 KO cells, suggesting that YKT6 and STX17 are independently required for fusion. YKT6 formed a SNARE complex with SNAP29 and lysosomal STX7, both of which are required for autophagosomal fusion. Recruitment of YKT6 to autophagosomes depends on its N-terminal longin domain but not on the C-terminal palmitoylation and farnesylation that are essential for its Golgi localization. These findings suggest that two independent SNARE complexes mediate autophagosome–lysosome fusion.

scholarly journals VAMP3 and VAMP8 regulate the development and functionality of parasitophorous vacuoles housing Leishmania amazonensis

2020 ◽  
Author(s):  
Olivier Séguin ◽  
Linh Thuy Mai ◽  
Sidney W. Whiteheart ◽  
Simona Stäger ◽  
Albert Descoteaux
Keyword(s):  
Host Cell ◽  
Leishmania Amazonensis ◽  
Phagocytic Cells ◽  
Attachment Protein ◽  
Receptor Proteins ◽  
Cross Presentation ◽  
Data Support ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Factor Attachment Protein Receptor

ABSTRACTTo colonize mammalian phagocytic cells, the parasite Leishmania remodels phagosomes into parasitophorous vacuoles that can be either tight-fitting individual or communal. The molecular and cellular bases underlying the biogenesis and functionality of these two types of vacuoles are poorly understood. In this study, we investigated the contribution of host cell Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor proteins in the expansion and functionality of communal vacuoles as well as on the replication of the parasite. The differential recruitment patterns of Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor to communal vacuoles harboring L. amazonensis and to individual vacuoles housing L. major led us to further investigate the contribution of VAMP3 and VAMP8 in the interaction of Leishmania with its host cell. We show that whereas VAMP8 contributes to optimal expansion of communal vacuoles, VAMP3 negatively regulates L. amazonensis replication, vacuole size, as well as antigen cross-presentation. In contrast, neither proteins has an impact on the fate of L. major. Collectively, our data support a role for both VAMP3 and VAMP8 in the development and functionality of L. amazonensis-harboring communal parasitophorous vacuoles.

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