Related Experiment Video
Updated: May 13, 2026
11:48
Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes
Published on: May 31, 2018
Rab6a/a' are important Golgi regulators of pro-inflammatory TNF secretion in macrophages
Massimo Micaroni1, Amanda C Stanley, Tatiana Khromykh
1Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
Plos One
|February 26, 2013
Summary
Rab6 GTPases are crucial for organizing Golgi structure and facilitating the secretion of tumor necrosis factor (TNF) from inflammatory macrophages. Depleting Rab6 impairs TNF release and Golgi organization, highlighting its role in immune response.
Area of Science:
- Cell Biology
- Immunology
- Molecular Biology
Background:
- Lipopolysaccharide (LPS)-activated macrophages secrete pro-inflammatory cytokines like tumor necrosis factor (TNF), contributing to innate immunity and chronic inflammatory diseases.
- Understanding the intracellular trafficking and secretion pathways of TNF is critical for developing therapeutic strategies for inflammatory conditions.
- Rab GTPases, specifically Rab6a and Rab6a', are known to be involved in maintaining Golgi structure and mediating Golgi-associated trafficking.
Purpose of the Study:
- To investigate the role of Rab6 GTPases in the regulation of TNF trafficking and secretion in LPS-activated macrophages.
- To elucidate the specific mechanisms by which Rab6 influences Golgi organization and the transport of TNF from the trans-Golgi network (TGN).
Main Methods:
- Utilized siRNA and shRNA to deplete Rab6 expression in macrophages.
- Employed electron microscopy to analyze Golgi structure alterations.
- Assessed TNF secretion levels and cell surface delivery.
- Investigated Rab6 localization on TGN-derived carriers using Rab6-GFP and identified associated proteins like golgin p230.
Main Results:
- LPS stimulation selectively increased Rab6 expression.
- Rab6 depletion led to Golgi ribbon reorganization into compact, elongated stacks and significantly reduced TNF secretion.
- Rab6-GFP localized to TGN-derived tubular carriers, and its depletion or inactivation disrupted carrier egress and p230 association, impairing TNF transport.
Conclusions:
- Rab6 GTPases are essential for maintaining Golgi stack organization and efficient post-Golgi transport of TNF in macrophages.
- Rab6 functions at the TGN exit stage, potentially by stabilizing p230 on tubular carriers to facilitate TNF transport.
- These findings offer new insights into Rab6 function and the Golgi complex's role in cytokine secretion during inflammatory responses.
Related Concept Videos
01:24T Cell Types and Functions
When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
01:16TGF - β Signaling Pathway
The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
01:15Receptor Downregulation in MVBs
Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
02:26NF-κB-dependent Signaling Pathway
The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
01:28Inflammatory Response
An inflammatory response is a localized, nonspecific immune reaction that occurs when a tissue is injured. It is characterized by redness, swelling, heat, and pain, which are commonly called the cardinal signs and symptoms of inflammation. Inflammation can sometimes result in a loss of function.
Inflammation can be triggered by various stimuli, such as impact, abrasion, chemical irritation, infections, and extreme hot or cold temperatures. These can damage cells and connective tissue fibers,...
Inflammation can be triggered by various stimuli, such as impact, abrasion, chemical irritation, infections, and extreme hot or cold temperatures. These can damage cells and connective tissue fibers,...
01:20The JAK-STAT Signaling Pathway
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...