title: ARF1 and ARF3 are required for the integrity of recycling endosomes and the recycling pathway.
abstract: Small GTPases ARF1 and ARF3 localize mainly to the Golgi apparatus, where they trigger formation of coated carrier vesicles. We previously showed that BIG2, a guanine nucleotide exchange factor specific for ARF1 and ARF3, localizes not only to the trans-Golgi network (TGN) but also to recycling endosomes, where it is involved in regulating the integrity of recycling endosomes. However, it is not yet clear whether ARF1 and ARF3 act downstream of BIG2 to ensure endosome integrity. In this study, we show that EGFP-tagged ARF1 and ARF3 localize to endosomal compartments containing endocytosed transferrin. We further demonstrate that simultaneous depletion of ARF1 and ARF3 induces tubulation of recycling endosomal compartments positive for transferrin receptor, Rab4, and Rab11, but does not significantly affect the integrity of the Golgi apparatus or early or late endosomes. Moreover, the simultaneous depletion of ARF1 and ARF3 suppresses recycling of transferrin but does not affect either its endocytosis or the retrograde transport of TGN38 from early/recycling endosomes to the TGN. In addition, depletion of ARF1 and ARF3 does not affect retrograde transport of CD4-furin from late endosomes to the TGN, or of endocytosed EGF from late endosomes to lysosomes. These results indicate that ARF1 and ARF3 are redundantly required for the integrity of recycling endosomes, and that they regulate transferrin recycling from endosomes to the plasma membrane, but not retrograde transport from endosomal compartments to the TGN.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Yumika
authors.initials: Y
authors.lastname: Kondo
authors.forename: Ayako
authors.initials: A
authors.lastname: Hanai
authors.forename: Waka
authors.initials: W
authors.lastname: Nakai
authors.forename: Yohei
authors.initials: Y
authors.lastname: Katoh
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakayama
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Shin
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020727:ADP-Ribosylation Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006056:Golgi Apparatus / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D021381:Protein Transport; D011990:Receptors, Transferrin / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D020695:rab4 GTP-Binding Proteins / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors; D011990:Receptors, Transferrin; D014168:Transferrin; D020691:rab GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C116687:ARF3 protein, human