The cell fate determinant numb interacts with EHD/Rme-1 family proteins and has a role in endocytic recycling.
The adaptor protein Numb is necessary for the cell fate specification of progenitor cells in the Drosophila nervous system. Numb is evolutionarily conserved and previous studies have provided evidence for a similar functional role during mammalian development. The Numb protein has multiple protein-protein interaction regions including a phosphotyrosine binding (PTB) domain and a carboxy-terminal domain that contains conserved interaction motifs including an EH (Eps15 Homology) domain binding motif and alpha-adaptin binding site. In this study we identify the EHD/Rme-1/Pincher family of endocytic proteins as Numb interacting partners in mammals and Drosophila. The EHD/Rme-1 proteins function in recycling of plasma membrane receptors internalized by both clathrin-mediated endocytosis and a clathrin-independent pathway regulated by ADP ribosylation factor 6 (Arf6). Here we report that Numb colocalizes with endogenous EHD4/Pincher and Arf6 and that Arf6 mutants alter Numb subcellular localization. In addition, we present evidence that Numb has a novel function in endosomal recycling and intracellular trafficking of receptors.
Smith
Christian A
CA
Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8.
Dho
Sascha E
SE
Donaldson
Julie
J
Tepass
Ulrich
U
McGlade
C Jane
CJ
D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000032:analysis / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000276:immunology; D004705:Endocytosis; D006367:HeLa Cells; D006801:Humans; D007605:Juvenile Hormones / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008322:Mammals / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D025941:Protein Interaction Mapping; D034622:RNA Interference; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D033921:Vesicular Transport Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
D000089982:ADP-Ribosylation Factor 6; D033942:Adaptor Proteins, Vesicular Transport; D029721:Drosophila Proteins; D007605:Juvenile Hormones; C496522:Past1 protein, Drosophila; D015375:Receptors, Interleukin-2; D033921:Vesicular Transport Proteins; C060606:numb protein, Drosophila; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human