Type II transforming growth factor-β receptor recycling is dependent upon the clathrin adaptor protein Dab2

SG Penheiter, R Deep Singh, CE Repellin… - Molecular biology of …, 2010 - Am Soc Cell Biol
SG Penheiter, R Deep Singh, CE Repellin, MC Wilkes, M Edens, PH Howe, RE Pagano…
Molecular biology of the cell, 2010Am Soc Cell Biol
Transforming growth factor (TGF)-β family proteins form heteromeric complexes with
transmembrane serine/threonine kinases referred to as type I and type II receptors. Ligand
binding initiates a signaling cascade that generates a variety of cell type-specific
phenotypes. Whereas numerous studies have investigated the regulatory activities
controlling TGF-β signaling, there is relatively little information addressing the endocytic and
trafficking itinerary of TGF-β receptor subunits. In the current study we have investigated the …
Transforming growth factor (TGF)-β family proteins form heteromeric complexes with transmembrane serine/threonine kinases referred to as type I and type II receptors. Ligand binding initiates a signaling cascade that generates a variety of cell type-specific phenotypes. Whereas numerous studies have investigated the regulatory activities controlling TGF-β signaling, there is relatively little information addressing the endocytic and trafficking itinerary of TGF-β receptor subunits. In the current study we have investigated the role of the clathrin-associated sorting protein Disabled-2 (Dab2) in TGF-β receptor endocytosis. Although small interfering RNA-mediated Dab2 knockdown had no affect on the internalization of various clathrin-dependent (i.e., TGF-β, low-density lipoprotein, or transferrin) or -independent (i.e., LacCer) cargo, TGF-β receptor recycling was abrogated. Loss of Dab2 resulted in enlarged early endosomal antigen 1-positive endosomes, reflecting the inability of cargo to traffic from the early endosome to the endosomal recycling compartment and, as documented previously, diminished Smad2 phosphorylation. The results support a model whereby Dab2 acts as a multifunctional adaptor in mesenchymal cells required for TGF-β receptor recycling as well as Smad2 phosphorylation.
Am Soc Cell Biol