[HTML][HTML] Sequence-dependent sorting of recycling proteins by actin-stabilized endosomal microdomains

MA Puthenveedu, B Lauffer, P Temkin, R Vistein… - Cell, 2010 - cell.com
Cell, 2010cell.com
The functional consequences of signaling receptor endocytosis are determined by the
endosomal sorting of receptors between degradation and recycling pathways. How
receptors recycle efficiently, in a sequence-dependent manner that is distinct from bulk
membrane recycling, is not known. Here, in live cells, we visualize the sorting of a
prototypical sequence-dependent recycling receptor, the beta-2 adrenergic receptor, from
bulk recycling proteins and the degrading delta-opioid receptor. Our results reveal a …
Summary
The functional consequences of signaling receptor endocytosis are determined by the endosomal sorting of receptors between degradation and recycling pathways. How receptors recycle efficiently, in a sequence-dependent manner that is distinct from bulk membrane recycling, is not known. Here, in live cells, we visualize the sorting of a prototypical sequence-dependent recycling receptor, the beta-2 adrenergic receptor, from bulk recycling proteins and the degrading delta-opioid receptor. Our results reveal a remarkable diversity in recycling routes at the level of individual endosomes, and indicate that sequence-dependent recycling is an active process mediated by distinct endosomal subdomains distinct from those mediating bulk recycling. We identify a specialized subset of tubular microdomains on endosomes, stabilized by a highly localized but dynamic actin machinery, that mediate this sorting, and provide evidence that these actin-stabilized domains provide the physical basis for a two-step kinetic and affinity-based model for protein sorting into the sequence-dependent recycling pathway.
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