A tubular endosomal fraction from rat liver: Biochemical evidence of receptor sorting by default

Vergés, Marcel; Havel, Richard J.; Mostov, Keith E.

doi:10.1073/pnas.96.18.10146

Cited by 43 publications

(52 citation statements)

References 37 publications

(45 reference statements)

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“…This compartment is enriched in basolaterally endocytosed IgA and depleted of TfR with respect to the CE. Ultrastuctural studies in MDCK cells (5) and cell fractionation of rat liver suggested that the ARE and tubular CE probably represent a single compartment that might be divided into different domains (5,36). This was largely based on the observation that whenever TfR and IgA colocalized, their relative concentrations appeared to be the same.…”

Section: Discussionmentioning

confidence: 98%

rab4 Regulates Transport to the Apical Plasma Membrane in Madin-Darby Canine Kidney Cells

Mohrmann

Leijendekker

Gerez

et al. 2002

Journal of Biological Chemistry

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The small GTPase rab4 is associated with early endosomes and regulates membrane recycling in fibroblasts. rab4 is present in epithelial cells; however, neither its localization nor function has been established in this cell type. We transfected Madin-Darby canine kidney cells with rab4, the GTPase-deficient mutant rab4Q67L, and the dominant negative mutant rab4S22N that poorly binds guanine nucleotides. Confocal immunofluorescence microscopy showed that rab4 was concentrated on internal structures at the lateral side of the cell around the nucleus. Quantitative immunoelectron microscopy revealed that the majority of rab4 was localized in the upper third of the cytoplasm. In cell surface binding experiments with 125 I-transferrin, we found a redistribution of transferrin receptor from the basolateral to the apical plasma membrane in cells expressing rab4 and rab4Q67L. After accumulation of transferrin at 16°C in basolateral early endosomes, rab4 and rab4Q67L increased the amount of apically targeted transferrin receptor. A qualitatively similar effect was obtained in control cells treated with brefeldin A. The effects of brefeldin A and rab4 on apical targeting of transferrin receptor were not additive, suggesting that brefeldin A and rab4 may act in the same transport pathway from common endosomes.

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Section: Discussionmentioning

confidence: 98%

rab4 Regulates Transport to the Apical Plasma Membrane in Madin-Darby Canine Kidney Cells

Mohrmann

Leijendekker

Gerez

et al. 2002

Journal of Biological Chemistry

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“…In contrast to the uncoupling of mammalian LDL from LDLR in sorting endosomes, HDLp remains attached to its receptor despite the decrease in lumenal pH. Endosome tubulation followed by iterative fractionation of membrane-anchored recycling receptors results in efficient receptor recycling by default (Dunn et al, 1989;Verges et al, 1999). Consequently, ligands that remain coupled to such receptors are recycled as well.…”

Section: Discussionmentioning

confidence: 99%

Insect lipoprotein follows a transferrin-like recycling pathway that is mediated by the insect LDL receptor homologue

Hoof

Rodenburg

Horst

2002

Journal of Cell Science

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The lipoprotein of insects, high-density lipophorin (HDLp), is homologous to that of mammalian low-density lipoprotein (LDL) with respect to its apolipoprotein structure. Moreover, an endocytic receptor for HDLp has been identified (insect lipophorin receptor, iLR) that is homologus to the LDL receptor. We transfected LDL-receptor-expressing CHO cells with iLR cDNA to study the endocytic uptake and intracellular pathways of LDL and HDLp simultaneously. Our studies provide evidence that these mammalian and insect lipoproteins follow distinct intracellular routes after receptor-mediated endocytosis. Multicolour imaging and immunofluorescence was used to visualize the intracellular trafficking of fluorescently labeled ligands in these cells. Upon internalization, which can be completely inhibited by human receptor-associated protein (RAP), mammalian and insect lipoproteins share endocytic vesicles. Subsequently, however, HDLp evacuates the LDL-containing endosomes. In contrast to LDL, which is completely degraded in lysosomes after dissociating from its receptor, both HDLp and iLR converge in a nonlysosomal juxtanuclear compartment. Colocalization studies with transferrin identified this organelle as the endocytic recycling compartment via which iron-depleted transferrin exits the cell. Fluorescently labeled RAP is also transported to this recycling organelle upon receptor-mediated endocytosis by iLR. Internalized HDLp eventually exits the cell via the recycling compartment, a process that can be blocked by monensin, and is re-secreted with a t½of ∼13 minutes. From these observations, we conclude that HDLp is the first non-exchangeable apolipoprotein-containing lipoprotein that follows a transferrin-like recycling pathway despite the similarities between mammalian and insect lipoproteins and their receptors.

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“…Ultrastructural studies in MDCK cells and cell fractionation of rat liver suggested that the ARE and tubular CE represent a single compartment that is subdivided into different domains Verges et al, 1999). By contrast, the non-overlapping or partially overlapping distribution of distinct SAC-associated markers, such as various Rab proteins, emphasized the subcompartmentalization of the SAC (van IJzendoorn and Hoekstra, 1999).…”

Section: The Subapical Compartment(s)mentioning

confidence: 99%

The subapical compartment: a traffic center in membrane polarity development

Hoekstra

Tyteca

IJzendoorn

2004

Journal of Cell Science

131

132

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IntroductionPolarity is a ubiquitous feature of the biology of eukaryotic cells and entails the establishment and maintenance of spatial and functional asymmetry, triggered by cues from the external and intracellular environments. For example, cell movement in response to chemoattractants causes asymmetric shape changes, generating a leading edge that protrudes at the front of the cell and a rear edge that retracts (Lauffenburger and Horwitz, 1996). Instrumental in this is the establishment of membrane polarity. Molecules such as (glyco)sphingolipids segregate to the two opposing membrane surfaces (GomezMouton et al., 2001) and, by virtue of their ability to organize microdomains, may establish a platform for recruitment of the different molecular machineries required at these locations. Polarity is also apparent in neuronal cells, in which membrane domains are segregated by a diffusion barrier formed by a row of protein 'pickets' assembled on a membrane-cytoskeletal meshwork at the axonal initial segment (Nakada et al., 2003). However, most attention has focused on epithelial cells and it is these that perhaps best exemplify the principles of cell polarity, displaying asymmetric cellular morphology, molecular composition and functional properties.Epithelial cells line many tissues and simultaneously face different environments: the lumen on one side, and adjacent cells and underlying connective tissue on the other. Accordingly, compartmentalization of the cell surface and hence the operation of distinctly localized sorting and retention mechanisms are crucial for their function. Signals triggered by extracellular matrix and cell-cell cues, and relayed by key players such as integrins and E-cadherin-catenin complexes, respectively, cause the establishment of specific intercellular junctions, rearrange the cytoskeletal architecture, and activate sorting mechanisms to generate the so-called apical and basolateral plasma membrane domains (Knust, 2002;Mostov et al., 2003;Nelson, 2003). Tight junctions separate these membrane domains, preventing mixing of membrane proteins and (outer leaflet) lipids between them. Complex signaling and sorting machineries regulate transport to and from either domain. In addition, the apical and basolateral domains communicate by transcytosis, the extent of which depends on the cell type. Here, we briefly summarize what is known about these mechanisms and focus on the role of the subapical compartment (SAC), a subcellular trafficking center that is thought to orchestrate these complex trafficking pathways and is required for the generation and maintenance of epithelial membrane polarity. Endocytosis and polarity: organization and pathwaysPolarization of epithelial Madin-Darby canine kidney (MDCK) cells establishes separate apical and basolateral membrane domains, but also results in a sixfold increase in the surface area of the lateral membrane (Vega-Salas et al., 1987). This demands high levels of membrane biogenesis, which relies on a variety of closely interconnected signaling, bios...

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A tubular endosomal fraction from rat liver: Biochemical evidence of receptor sorting by default

Cited by 43 publications

References 37 publications

rab4 Regulates Transport to the Apical Plasma Membrane in Madin-Darby Canine Kidney Cells

rab4 Regulates Transport to the Apical Plasma Membrane in Madin-Darby Canine Kidney Cells

Insect lipoprotein follows a transferrin-like recycling pathway that is mediated by the insect LDL receptor homologue

The subapical compartment: a traffic center in membrane polarity development

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