title: Numb controls integrin endocytosis for directional cell migration with aPKC and PAR-3.
abstract: Migrating cells extend protrusions to establish new adhesion sites at their leading edges. One of the driving forces for cell migration is the directional trafficking of cell-adhesion molecules such as integrins. Here, we show that the endocytic adaptor protein Numb is an important component of the machinery for directional integrin trafficking in migrating cells. Numb binds to integrin-betas and localizes to clathrin-coated structures (CCSs) at the substratum-facing surface of the leading edge. Numb inhibition by RNAi impairs both integrin endocytosis and cell migration toward integrin substrates. Numb is regulated by phosphorylation since the protein is released from CCSs and no longer binds integrins when phosphorylated by atypical protein kinase C (aPKC). Because Numb interacts with the aPKC binding partner PAR-3, we propose a model in which polarized Numb phosphorylation contributes to cell migration by directing integrin endocytosis to the leading edge.
authors.affiliation: Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa, Nagoya, Aichi 466-8550, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishimura
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology; D002522:Chlorocebus aethiops; D022163:Clathrin-Coated Vesicles / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D022001:Focal Adhesions / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D039641:Integrin beta Chains / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D014709:Vero Cells
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D039641:Integrin beta Chains; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C113026:NUMB protein, human; C509689:PARD3 protein, human; C115015:PKC-3 protein; D011493:Protein Kinase C