Abstract:
BACKGROUND INFORMATION:αvβ5 integrin and Mer tyrosine kinase (MerTK) receptors reside at the apical surface of the retinal pigment epithelium (RPE) in the eye to promote the diurnal, synchronised phagocytosis of shed photoreceptor outer segment fragments (POS) that is critical for vision. Phagocytosis assays studying RPE cells in culture have defined roles for αvβ5 in POS surface binding and for MerTK in engulfment of bound POS. Both receptors have thus far only been studied separately. It is therefore unknown if αvβ5 integrin activity in POS binding is independent of the engulfment function of RPE cells. This study investigates how increasing αvβ5 receptor levels affect POS binding and internalisation by wild-type (wt), αvβ5- or MerTK-deficient RPE. RESULTS:β5 integrin-green fluorescent protein (β5-GFP) fusion proteins formed heterodimeric receptors with endogenous αv integrin subunits at the apical surface of mouse or rat RPE cells that co-immunoprecipitated focal adhesion kinase and redistributed with bound POS such as endogenous αvβ5 receptors. In β5(-/-) RPE cells, de novo formation of αvβ5-GFP receptors restored POS binding and internalisation up to, but not, above wt POS uptake levels. In wt RPE cells, increasing levels of αvβ5 surface receptors by over-expressing β5-GFP only moderately stimulated POS binding, even if POS internalisation was inhibited pharmacologically or by lowering incubation temperatures. In contrast, the same increase in αvβ5 receptor levels dramatically enhanced POS binding of RPE cells lacking MerTK. Furthermore, decreasing MerTK expression by RNA interference increased POS binding to endogenous αvβ5 receptors of wt RPE cells. CONCLUSIONS:Expressing β5-GFP is sufficient to reverse phagocytic deficiencies of RPE cells derived from β5(-/-) mice, indicating that these cells do not irreversibly lose other components of the phagocytic machinery. RPE cells expressing the engulfment receptor MerTK control POS binding by limiting activity of endogenous αvβ5 and αvβ5-GFP integrins, although they reside at the apical, phagocytic surface. In contrast, RPE cells permanently or transiently losing MerTK expression lack this regulatory mechanism and bind excess POS via surface αvβ5 receptors. Taken together, these data reveal a novel feedback mechanism that restricts binding of POS to surface αvβ5 integrin receptors in RPE cells.
journal_name
Biol Celljournal_title
Biology of the cellauthors
Nandrot EF,Silva KE,Scelfo C,Finnemann SCdoi
10.1111/boc.201100076subject
Has Abstractpub_date
2012-06-01 00:00:00pages
326-41issue
6eissn
0248-4900issn
1768-322Xjournal_volume
104pub_type
杂志文章abstract::Cells sense and respond to the biochemical and physical properties of the extracellular matrix (ECM) through adhesive structures that bridge the cell cytoskeleton and the surrounding environment. Integrin-mediated adhesions interact with specific ECM proteins and sense the rigidity of the substrate to trigger signalli...
journal_title:Biology of the cell
pub_type: 杂志文章,评审
doi:10.1111/boc.201700060
更新日期:2018-03-01 00:00:00
abstract:BACKGROUND INFORMATION:NPY (neuropeptide Y) may have an effect on the properties of vascular endothelial cells such as pro-angiogenic effects and potentiation of noradrenaline-induced vasoconstriction. In HUVEC (human umbilical-vein endothelial cells), immunoreactive neuropeptide Y has been detected, but NPY synthesis,...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20040102
更新日期:2005-06-01 00:00:00
abstract::Extensive developmentally programmed DNA rearrangements, including thousands of internal deletions, occur in the differentiating somatic macronucleus in Tetrahymena thermophila. Some deletion systems involve the use of multiple alternative deletion sites. We report here the cloning and the sequences of three new alter...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(96)84773-3
更新日期:1996-01-01 00:00:00
abstract::Aspergillus fumigatus, the causative agent of human aspergillosis, binds to and degrades basement membrane laminin. Using immunoelectron microscopy, laminin binding appeared to be associated with the cell wall expansions of resting conidia, and progressively extended to the outer electron dense layer of the conidial w...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/s0248-4900(05)80189-3
更新日期:1993-01-01 00:00:00
abstract::Our knowledge of cell signalling pathways in the molluscan immune system and their response to immunological challenge is currently poor. The present study focused on the Protein Kinase C (PKC) pathway in the immune cells (haemocytes) of Lymnaea stagnalis and its response following exposure to bacterial lipopolysaccha...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/j.biolcel.2003.09.001
更新日期:2003-11-01 00:00:00
abstract::It is now well established that malignant transformation of eucaryotic cells is concomitant with typical alterations of glycosylation and the expression pattern of endogenous lectins. In parallel, oncogene transfection studies revealed a correlation between the expression of some of these genes, the transformed state ...
journal_title:Biology of the cell
pub_type: 杂志文章,评审
doi:10.1111/j.1768-322x.1993.tb00899.x
更新日期:1993-01-01 00:00:00
abstract::ESCRTs (endosomal sorting complexes required for transport) were first discovered in yeast and are known to be required in the biogenesis of the MVB (multivesicular body). Most ESCRT research has been carried out in vitro using models such as yeast and mammalian cells in culture. The role of the ESCRTs genes in endoso...
journal_title:Biology of the cell
pub_type: 杂志文章,评审
doi:10.1042/BC20090145
更新日期:2010-01-13 00:00:00
abstract::Somatostatin-immunoreactive cells were localized on semithin and ultrathin sections of Epon-embedded samples of perch gastric mucosa, classically fixed with aldehydes and osmium tetroxide. On semithin sections, somatostatin cells were identified by using the immunoperoxidase method. The ultrastructural localization of...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1111/j.1768-322x.1985.tb00375.x
更新日期:1985-01-01 00:00:00
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journal_title:Biology of the cell
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doi:10.1042/BC20070168
更新日期:2009-02-01 00:00:00
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journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1111/boc.201100099
更新日期:2012-08-01 00:00:00
abstract:BACKGROUND INFORMATION:ROS (reactive oxygen species) as well as components of the antioxidant redox systems may act as signals. To link acute environmental change with gene expression, changes in ROS and GSH/GSSG (reduced/oxidized glutathione) level were measured upon acute changes in temperature or oxygen availability...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20100145
更新日期:2011-08-01 00:00:00
abstract::The quick-freeze, freeze-fracture, deep-etching and rotary replication techniques were used to analyze the structural organization of Giardia duodenalis. The surface of the flagella was rugous, in contrast to the cell body surface which was smooth. The ventral region was characterized in more detail, exposing the laye...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(96)84780-0
更新日期:1996-01-01 00:00:00
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journal_title:Biology of the cell
pub_type: 杂志文章,评审
doi:10.1016/s0248-4900(02)00006-0
更新日期:2002-10-01 00:00:00
abstract::Arabinoxylans were localised by immunocytochemistry using polyclonal antibodies in the cell walls of the apical internode of maize after degradation in the rumen. In order to understand the significance of arabinoxylan in digestibility property, two lines of maize differing in digestibility were used. Wide variations ...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1111/j.1768-322x.1996.tb00988.x
更新日期:1996-01-01 00:00:00
abstract::The aim of a large number of studies on G protein-coupled receptors was centered on understanding the structural basis of their main functional properties. Here, we will briefly review the results obtained on the alpha1-adrenergic receptor subtypes belonging to the rhodopsin-like family of receptors. These findings co...
journal_title:Biology of the cell
pub_type: 杂志文章,评审
doi:10.1016/j.biolcel.2004.03.009
更新日期:2004-06-01 00:00:00
abstract:BACKGROUND INFORMATION:The identification of a source of stem cells able to regenerate skeletal muscle was the goal of numerous studies with the aim to develop new therapeutic approaches for genetic muscle diseases or muscle injuries. A series of studies have demonstrated that stem cells derived from various tissues ma...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20100112
更新日期:2011-11-01 00:00:00
abstract::Immunofluorescent techniques have been used in the analysis of DNA-RNA hybrids occurrence and its relationship to transcriptional events on polytene chromosomes of Drosophila subobscura. We have studied the distribution of these hybrids on uninduced/induced chromosomes. Two different indirect immunofluorescence method...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(92)90140-v
更新日期:1992-01-01 00:00:00
abstract::Isolated cells from the proximal tubule have previously been used to study specific renal physiological processes. Here we analysed the structural changes induced by mechanical isolation on rat proximal tubule cells. As major modifications we detected: 1) a redistribution of brush border microvilli, which spread out o...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(92)90026-w
更新日期:1992-01-01 00:00:00
abstract::The distribution of viral RNA molecules in HeLa cells infected with adenovirus type 5 (Ad5) was determined by in situ hybridization at the ultrastructural level at an intermediate stage of nuclear transformation, when viral DNA synthetic activities were maximal but progeny viruses were still sparse. Transcription site...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(91)90060-z
更新日期:1991-01-01 00:00:00
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journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(92)90200-k
更新日期:1992-01-01 00:00:00
abstract::beta-Catenin was initially characterized as a protein interacting with the cadherin cytoplasmic tail and regulating cell-cell contacts and actin cytoskeleton interactions. Moreover, the gene coding for the Drosophila orthologue of beta-catenin, armadillo, was independently identified downstream of wingless in the segm...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20040531
更新日期:2005-12-01 00:00:00
abstract:BACKGROUND INFORMATION:Substantial evidence indicates the existence of NCSCs (neural crest-derived stem cells) in embryonic mandibular processes; however, they have not been fully investigated or isolated. The aim of the present study was to isolate stem cells from mandibular process during embryonic development by MAC...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20060012
更新日期:2006-10-01 00:00:00
abstract::We used a high-resolution STEM to attempt to recognize the spatial localization of the macromolecular components of ribosomes isolated from Tetrahymena pyriformis. Images obtained either by the annular dark field detector or by the ratio-contrast mode (Z-contrast) show a ribosome as constituted of rounded dark areas, ...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1111/j.1768-322x.1984.tb00271.x
更新日期:1984-01-01 00:00:00
abstract:BACKGROUND INFORMATION:In eukaryotic cells, autophagy is considered a lysosomal catabolic process which participates in the degradation of intracellular components in a vacuolar structure termed autolysosome. This pathway plays a significant role in the erythropoiesis process, contributing to the clearance of some orga...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1111/boc.201500058
更新日期:2016-04-01 00:00:00
abstract:BACKGROUND INFORMATION:AQP10 (aquaporin 10) is a new member of water channels and two different transcripts have been reported. The difference between these transcripts is in the presence or the absence of an insertion of 475 nt, which leads to a translation frame shift resulting in a different termination of amino aci...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20040091
更新日期:2005-11-01 00:00:00
abstract::Effect of estradiol-17 beta on rat vaginal epithelial cells (VEC) was studied by transmission electron microscopy. During the normal estrous cycle in adult rats keratinization and exfoliation of VEC was observed only in the estrus phase, though tonofilament bundles were seen distributed in the cytoplasm of the VEC dur...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:
更新日期:1989-01-01 00:00:00
abstract:BACKGROUND:Integrins are transmembrane alphabeta heterodimer receptors that function as structural and functional bridges between the cytoskeleton and ECM (extracellular matrix) molecules. The RGD (arginine-glycine-aspartate tripeptide motif)-dependent integrin alpha8beta1 has been shown to be involved in various cell ...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1042/BC20090060
更新日期:2009-09-14 00:00:00
abstract::Inside-out porcine thyroid follicles in culture undergo polarity reversal after being embedded in collagen gel. The newly-formed follicles reexpress some specific thyroid functions lost in inside-out follicles (Chambard et al., 1984. We present here an ultrastructural study of the inversion of polarity in this model s...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1111/j.1768-322x.1986.tb00463.x
更新日期:1986-01-01 00:00:00
abstract::Peroxisomes are present in most eukaryotic cell types, and have different enzymatic content and metabolic functions throughout the life scale. The endosymbiotic origin of these DNA-devoid organelles is supported by evolutionary data concerning genes encoding not only most peroxisomal proteins, but also several transcr...
journal_title:Biology of the cell
pub_type: 杂志文章,评审
doi:10.1016/s0248-4900(00)01083-2
更新日期:2000-09-01 00:00:00
abstract::The pH-related change in morphology of vinblastine (VLB)-induced paracrystals formed in Chinese hamster ovary (CHO) cells was examined immunohistochemically in order to determine both the mechanism of tubulin crystallization and the influence of acidic pHs on cytoskeletal microtubules. Lowering the extracellular pH (p...
journal_title:Biology of the cell
pub_type: 杂志文章
doi:10.1016/0248-4900(94)90066-3
更新日期:1994-01-01 00:00:00