Caenorhabditis elegans RME-6 is a novel regulator of RAB-5 at the clathrin-coated pit

Sato, Miyuki; Sato, Ken; Fonarev, Paul; Huang, Chih-Jen; Liou, Willisa; Grant, Barth D.

doi:10.1038/ncb1261

Cited by 151 publications

(172 citation statements)

References 47 publications

Supporting

Mentioning

160

Contrasting

Unclassified

Order By: Relevance

“…There are three Vps9-domain containing proteins in the nematode, rme-6, rabx-5, and tag-333 41 . RME-6 and RABX-5 are both homologues of mammalian RabEx-5 and are required for generation of RAB-5(+) endosomes in coelomocytes 42 and in the somatic sheath cells (Supplementary Figure S1). Surprisingly, neither the single mutants rme-6, rabx-5 or tag-333 nor the triple mutant rme-6 (b1014); tag-333(gk431); rabx-5(RNAi) worms showed any defects in corpse removal, suggesting that this class of proteins is not required for RAB-5 function during apoptotic cell clearance.…”

Section: Rab-5 and Rab-7 Are Required For Efficient Phagosome Maturationmentioning

confidence: 99%

A pathway for phagosome maturation during engulfment of apoptotic cells

et al. 2008

View full text Add to dashboard Cite

The efficient removal of apoptotic cells is critical for the physiological well-being of the organism 1 Ã 4 ; defects in corpse removal have been linked to autoimmune disease 4,5 . While several players regulating the early steps of corpse recognition and internalization have been characterized 6 , the molecules and mechanisms relevant to the subsequent processing of the internalized corpses are poorly understood. Here, we identify a novel pathway for the processing of internalized apoptotic cells in C. elegans and in mammals. First, we show that RAB-5 and RAB-7 are sequentially recruited to phagosomes containing apoptotic corpses as they mature within phagocytes, and that both proteins are required for efficient corpse clearance. We then used targeted genetic screens to identify players regulating the recruitment and/or retention of Rab5 and Rab7 to phagosomes. Seven members of the HOPS complex (a Rab7 activator/effector complex) were required for Rab7 localization or retention on phagosomes. In an effort to identify factors that regulate Rab5 recruitment, we undertook an unbiased reverse genetic screen and identified 61 genes potentially required for corpse removal. In-depth analysis of two candidate genes, vps-34 and dyn-1/ dynamin, showed accumulation of internalized, but undegraded corpses within abnormal phagosomes that are defective in RAB-5 recruitment. Using a series of genetic and biochemical experiments in worms and mammalian cells, we ordered these proteins in a pathway, with DYN-1 functioning upstream of VPS-34, in the recruitment/retention of Rab5 to the nascent phagosome. Further, we identified a novel biochemical complex containing Vps34, dynamin and Rab5 GDP , providing a mechanism for Rab5 recruitment to the nascent phagosome.Removal of apoptotic cells (engulfment) is an essential process that occurs throughout life in multi-cellular animals as part of development, homeostasis, and wound healing1Ã4 , 7 , 8. Engulfment) can be broken down into a series of steps, comprising recognition, internalization, phagosome maturation and finally lysosomal degradation of the apoptotic cell by the phagocyte. In mammals, impaired clearance of apoptotic cell corpses can lead to exposure of autoantigens, resulting in onset of autoimmune diseases, such as systemic lupus erythematosus 4,9,10 . Modulation of the engulfment process is therefore a potential therapeutic target in these conditions. One of the fundamental challenges in understanding how defects in engulfment of apoptotic cells translates into diseased states is the identification of critical players involved in corpse removal and how these proteins orchestrate the different stages of engulfment.The nematode C. elegans represents a powerful genetic tool for the study of programmed cell death 11,12 . Large numbers of cells are induced to die during two periods in the life of a worm: during embryonic and larval morphogenesis and during germ cell development 13 . Genetic studies have identified two evolutionarily conserved signaling pathways invol...

show abstract

Section: Rab-5 and Rab-7 Are Required For Efficient Phagosome Maturationmentioning

confidence: 99%

A pathway for phagosome maturation during engulfment of apoptotic cells

et al. 2008

View full text Add to dashboard Cite

show abstract

“…For example, the RME-6 exchange factor for Rab5 was shown previously to bind to the APA-2 subunit of the AP-2 complex. Although unlikely to function directly in vesicle formation, the presence of RME-6 at clathrin-coated pits likely enhances Rab5 activity, which is necessary for vesicle fusion with the endosome (35). In an analogous fashion, RME-4 also binds to APA-2 and activates Rab35, which functions later in cargo recycling (36).…”

Section: The Fei Adaptor Complex Regulates Protein Sorting In the Endmentioning

confidence: 99%

Regulation of ubiquitin-dependent cargo sorting by multiple endocytic adaptors at the plasma membrane

Mayers¹,

Wang²,

Pramanik³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Endocytic protein trafficking is directed by sorting signals on cargo molecules that are recognized by cytosolic adaptor proteins. However, the steps necessary to segregate the variety of cargoes during endocytosis remain poorly defined. Using Caenorhabditis elegans, we demonstrate that multiple plasma membrane endocytic adaptors function redundantly to regulate clathrin-mediated endocytosis and to recruit components of the endosomal sorting complex required for transport (ESCRT) machinery to the cell surface to direct the sorting of ubiquitin-modified substrates. Moreover, our data suggest that preassembly of cargoes with the ESCRT-0 complex at the plasma membrane enhances the efficiency of downstream sorting events in the endolysosomal system. In the absence of a heterooligomeric adaptor complex composed of FCHO, Eps15, and intersectin, ESCRT-0 accumulation at the cell surface is diminished, and the degradation of a ubiquitin-modified cargo slows significantly without affecting the rate of its clathrin-mediated internalization. Consistent with a role for the ESCRT machinery during cargo endocytosis, we further show that the ESCRT-0 complex accumulates at a subset of clathrin-coated pits on the surface of human cells. Our findings suggest a unique mechanism by which ubiquitin-modified cargoes are sequestered into the endolysosomal pathway.clathrin | multivesicular endosome

show abstract

“…Transgenic worm lines were made using the microparticle bombardment method into unc-119(ed3) mutant animals to establish low-copy integrated transgenic lines (76,77). Live worms were mounted on 2% (mass/vol) agarose pads with 10 mM levamisol as described previously (78). Multiwavelength fluorescence images were obtained using an Axiovert 200M (Carl Zeiss MicroImaging) microscope equipped with a digital CCD camera (QImaging; Rolera EM-C 2 ), captured using MetaMorph 7.7 software (Universal Imaging) and then deconvolved using AutoDeblur X3 software (AutoQuant Imaging).…”

Section: Methodsmentioning

confidence: 99%

A TOCA/CDC-42/PAR/WAVE functional module required for retrograde endocytic recycling

Bai

Grant

2015

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

Endosome-to-Golgi transport is required for the function of many key membrane proteins and lipids, including signaling receptors, small-molecule transporters, and adhesion proteins. The retromer complex is well-known for its role in cargo sorting and vesicle budding from early endosomes, in most cases leading to cargo fusion with the trans-Golgi network (TGN). Transport from recycling endosomes to the TGN has also been reported, but much less is understood about the molecules that mediate this transport step. Here we provide evidence that the F-BAR domain proteins TOCA-1 and TOCA-2 (Transducer of Cdc42 dependent actin assembly), the small GTPase CDC-42 (Cell division control protein 42), associated polarity proteins PAR-6 (Partitioning defective 6) and PKC-3/atypical protein kinase C, and the WAVE actin nucleation complex mediate the transport of MIG-14/Wls and TGN-38/TGN38 cargo proteins from the recycling endosome to the TGN in Caenorhabditis elegans. Our results indicate that CDC-42, the TOCA proteins, and the WAVE component WVE-1 are enriched on RME-1-positive recycling endosomes in the intestine, unlike retromer components that act on early endosomes. Furthermore, we find that retrograde cargo TGN-38 is trapped in early endosomes after depletion of SNX-3 (a retromer component) but is mainly trapped in recycling endosomes after depletion of CDC-42, indicating that the CDC-42-associated complex functions after retromer in a distinct organelle. Thus, we identify a group of interacting proteins that mediate retrograde recycling, and link these proteins to a poorly understood trafficking step, recycling endosome-to-Golgi transport. We also provide evidence for the physiological importance of this pathway in WNT signaling.retromer | endocytic recycling | endosome | toca | wave

show abstract

Caenorhabditis elegans RME-6 is a novel regulator of RAB-5 at the clathrin-coated pit

Cited by 151 publications

References 47 publications

A pathway for phagosome maturation during engulfment of apoptotic cells

A pathway for phagosome maturation during engulfment of apoptotic cells

Regulation of ubiquitin-dependent cargo sorting by multiple endocytic adaptors at the plasma membrane

A TOCA/CDC-42/PAR/WAVE functional module required for retrograde endocytic recycling

Contact Info

Product

Resources

About