Recent studies indicate that lipid droplets isolated from a variety of different cells are rich in proteins known to regulate membrane traffic. Among these proteins are multiple Rab GTPases. Rabs are GTP switches that regulate intracellular membrane traffic through an ability to control membrane-membrane docking as well as vesicle motility. Here we present evidence that the multiple Rabs associated with droplets have a function in regulating membrane traffic. Droplet Rabs are removed by Rab GDP-dissociation inhibitor (RabGDI) in a GDP-dependent reaction, and are recruited to Rab-depleted droplets from cytosol in a GTP-dependent reaction. Rabs also control the recruitment of the early endosome (EE) marker EEA1 from cytosol. We use an in vitro reconstitution assay to show that transferrin receptor positive EEs bind to the droplet in a GTP/Rab-dependent reaction that appears not to lead to membrane fusion. This docking reaction is insensitive to ATP(gamma s) but is blocked by ATP. Finally, we show that when GTP bound active or GDP bound inactive Rab5 is targeted to the droplet, the active form recruits EEA1. We conclude that the Rabs associated with droplets may be capable of regulating the transient interaction of specific membrane systems, probably to transport lipids between membrane compartments.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2676670 | PMC |
| http://dx.doi.org/10.1016/j.bbamcr.2007.02.004 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Veno-venous ECMO intervention for respiratory failure after trauma from a motor vehicle collision.
BMJ Case Rep
January 2025
Department of General Surgery, Royal Brisbane and Women's Hospital, Queensland Health, Brisbane, Queensland, Australia.
Extracorporeal membrane oxygenation (ECMO) has emerged as a salvage therapy in refractory respiratory failure. Within the literature, there is evidence to support the use of ECMO in severe thoracic trauma; however, there is minimal information on its applicability in mild to moderate thoracic trauma. This report describes a man in his 50s who suffered thoracic trauma following a motor vehicle accident, who, despite maximal medical therapy, experienced deterioration in respiratory function, requiring the commencement of veno-venous ECMO on day 5 post injury and subsequently achieved excellent functional recovery.
View Article and Find Full Text PDFSkin disease-associated GJB4 variants differentially influence connexin stability, cell viability and channel function.
J Physiol
January 2025
Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
Here we characterize seven Cx30.3 gene variants (R22H, S26Y, P61R, C86S, E99K, T130M and M190L) clinically associated with the rare skin disorder erythrokeratodermia variabilis et progressiva (EKVP) in tissue-relevant and differentiation-competent rat epidermal keratinocytes (REKs). We found that all variants, when expressed alone or together with wildtype (WT) Cx30.
View Article and Find Full Text PDFSNARE-Mediated Membrane Fusion Probed Using a Synthetic Organelle in the Living Bacterium.
Methods Mol Biol
January 2025
Université Paris Cité, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.
Studies on the mechanisms and regulation of functional assemblies of SNARE proteins mediating membrane fusion essentially make use of recombinant proteins and artificial phospholipid bilayers. We have developed an easy-to-use in vivo system reconstituting membrane fusion in living bacteria. It relies on the formation of caveolin-dependent intracytoplasmic cisternae followed by the controlled synthesis of members of the synaptic SNARE machinery.
View Article and Find Full Text PDF3D-Porous Electrocatalyst with Tip-Enhanced Electric Field Effect Enables High-Performance Proton Exchange Membrane Water Electrolyzer.
Adv Mater
January 2025
School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023, China.
Hydrogen evolution reaction (HER), as one of the most advanced methods for the green production of hydrogen, is greatly impeded by inefficient mass transfer. Here we present an efficiently reactant enriched and mass traffic system by integrating high-curvature Pt nanocones with 3D porous TiAl framework to enhance mass transfer rate. Theoretical simulations, in situ Raman spectroscopy and potential-dependent Fourier transform infrared spectroscopy results disclose that the strong local electric field induced by high-curvature Pt can greatly promote the HO supply rate during HER, resulting in ∼1.
View Article and Find Full Text PDFThe conserved K3 residue in the N-terminal region of Rab10 small GTPase is required for tubular endosome formation: N-terminal tagging causes Rab10 dysfunction.
J Cell Sci
January 2025
Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
Various N-terminal tags have often been used to identify the functions and localization of Rab small GTPases, but their impact on Rab proteins themselves has been poorly investigated. Here, we used a knockout (KO)-rescue approach to systematically evaluate the effect of N-terminal tagging of two Rabs, Rab10 and Rab27A, on Rab10-KO HeLa cells and Rab27A-deficient melanocytes (melan-ash cells), respectively. The results showed that all of the N-terminal-tagged Rab27A proteins mediated actin-based melanosome transport in the melan-ash cells, but none of the N-terminal-tagged Rab10 proteins fully rescued the defect in tubular endosome formation in the Rab10-KO cells.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!