The Dioxin receptor modulates Caveolin-1 mobilization during directional migration: role of cholesterolReportar como inadecuado




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Cell Communication and Signaling

, 12:57

First Online: 21 September 2014Received: 05 April 2014Accepted: 05 September 2014

Abstract

BackgroundAdhesion and migration are relevant physiological functions that must be regulated by the cell under both normal and pathological conditions. The dioxin receptor AhR has emerged as a transcription factor regulating both processes in mesenchymal, epithelial and endothelial cells. Indirect results suggest that AhR could cooperate not only with additional transcription factors but also with membrane-associated proteins to drive such processes.

ResultsIn this study, we have used immortalized and primary dermal fibroblasts from wild type AhR+-+ and AhR-null AhR?-? mice to show that AhR modulates membrane distribution and mobilization of caveolin-1 Cav-1 during directional cell migration. AhR co-immunoprecipitated with Cav-1 and a fraction of both proteins co-localized to detergent-resistant membrane microdomains DRM. Consistent with a role of AhR in the process, AhR?-? cells had a significant reduction in Cav-1 in DRMs. Moreover, high cell density reduced AhR nuclear levels and moved Cav-1 from DRMs to the soluble membrane in AhR+-+ but not in AhR?-? cells. Tyrosine-14 phosphorylation had a complex role in the mechanism since its upregulation reduced Cav-1 in DRMs in both AhR+-+ and AhR?-? cells, despite the lower basal levels of Y-Cav-1 in the null cells. Fluorescence recovery after photobleaching revealed that AhR knock-down blocked Cav-1 transport to the plasma membrane, a deficit possibly influencing its depleted levels in DRMs. Membrane distribution of Cav-1 in AhR-null fibroblasts correlated with higher levels of cholesterol and with disrupted membrane microdomains, whereas addition of exogenous cholesterol changed the Cav-1 distribution of AhR+-+ cells to the null phenotype. Consistently, higher cholesterol levels enhanced caveolae-dependent endocytosis in AhR-null cells.

ConclusionsThese results suggest that AhR modulates Cav-1 distribution in migrating cells through the control of cholesterol-enriched membrane microdomains. Our study also supports the likely possibility of membrane-related, transcription factor independent, functions of AhR.

KeywordsDioxin receptor Caveolin-1 Membrane microdomains Endocytosis Cholesterol AbbreviationsAhRDioxin receptor

Cav-1Caveolin-1, DRM, detergent resistant microdomains

FRAPFluorescence recovery after photobleaching

GFPGreen fluorescent protein

MbCDMethyl-?-cyclodextin

TfRTransferrin receptor

YFPYellow fluorescent protein

si-RNASmall interfering RNA

Electronic supplementary materialThe online version of this article doi:10.1186-s12964-014-0057-7 contains supplementary material, which is available to authorized users.

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Autor: Javier Rey-Barroso - Alberto Alvarez-Barrientos - Eva Rico-Leo - María Contador-Troca - José M Carvajal-Gonzalez - Asier 

Fuente: https://link.springer.com/







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