Rab11 regulates exocytosis of recycling vesicles at the plasma membrane.
Rab11 is known to associate primarily with perinuclear recycling endosomes and regulate recycling of endocytosed proteins. However, the recycling step in which Rab11 participates remains unknown. We show here that, in addition to causing tubulation of recycling endosomes, Rab11 depletion gives rise to accumulation of recycling carriers containing endocytosed transferrin and transferrin receptor beneath the plasma membrane. We also show that the carriers are transported from perinuclear recycling endosomes to the cell periphery along microtubules. Total internal reflection fluorescence microscopy of cells expressing EGFP-tagged transferrin receptor revealed that Rab11 depletion inhibits tethering and fusion of recycling carriers to the plasma membrane. Depletion of Sec15, which interacts with Rab11, or Exo70, both components of the exocyst tethering complex, leads to essentially the same phenotypes as those of Rab11 depletion. Thus, in addition to its role in recycling processes at perinuclear recycling endosomes, Rab11 is transported along microtubules to the cell periphery through association with recycling carriers, and directly regulates vesicle exocytosis at the plasma membrane in concert with the exocyst.
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501,  Japan.
Senye
S
Takahashi
Keiji
K
Kubo
Satoshi
S
Waguri
Atsuko
A
Yabashi
Hye-Won
HW
Shin
Yohei
Y
Katoh
Kazuhisa
K
Nakayama
D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D004705:Endocytosis; D005089:Exocytosis; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D021122:Protein Subunits / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011990:Receptors, Transferrin / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D022161:Transport Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D033921:Vesicular Transport Proteins / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
D049452:Green Fluorescent Proteins; D021122:Protein Subunits; D034741:RNA, Small Interfering; D011990:Receptors, Transferrin; D014168:Transferrin; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C547754:EXOC7 protein, human; C485184:enhanced green fluorescent protein