title: The Arf GTPase-activating protein SMAP1 promotes transferrin receptor endocytosis and interacts with SMAP2.
abstract: Arf GTPase-activating proteins (Arf GAP) play important roles in the formation of the membrane vesicles that traffic between subcellular membranous organelles. The small Arf GTPase-activating protein (SMAP) subfamily of Arf GAPs has two members, SMAP1 and SMAP2, in mammals. The present study investigated whether these two proteins may have an overlapping function in addition to their previously reported distinct functions. Results showed that the presence of either SMAP1 or SMAP2 was sufficient for endocytosis of the transferrin receptor, and that transferrin incorporation was impaired only by the absence of both SMAP1 and SMAP2. This suggests the involvement of both SMAP1 and SMAP2 in transferrin endocytosis. Results also demonstrated a physical association between SMAP1 and SMAP2, which might serve as a basis for a functional interaction, and identified the intramolecular domains responsible for this association.
authors.affiliation: Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kon
authors.affiliation: Medical Research Institute, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Henmi
authors.affiliation: Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
authors.forename: Tomo
authors.initials: T
authors.lastname: Funaki
authors.affiliation: Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Satake
authors.affiliation: Medical Research Institute, Tokyo Women's Medical University, Tokyo, Japan. Electronic address: tanabe.kenji@twmu.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Tanabe
mesh_terms: D000818:Animals; D002460:Cell Line; D004705:Endocytosis / Q000502:physiology*; D020690:GTPase-Activating Proteins / Q000378:metabolism* / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism* / Q000502:physiology*; D051379:Mice; D011485:Protein Binding; D011990:Receptors, Transferrin / Q000378:metabolism*
chemical_list: D020690:GTPase-Activating Proteins; D008565:Membrane Proteins; D011990:Receptors, Transferrin; C107022:SMAP1 protein, human; C553893:SMAP2 protein, human
keywords: Arf GTPase-activating protein; Clathrin; Endocytosis; Membrane traffic; Transferrin receptor