Supplemental Material

This article contains the following supporting material:

• Figure 1 - Expression of Arf1 or Arf1N52R does not cause an accumulation of MHCI-containing tubular endosomes.

  HeLa cells expressing Arf1-HA or Arf1N52R-HA were fixed and stained with antibodies to HA to detect Arf1 and to MHCI.

• Figure 2 - Arf6N48R and N48I cannot make protrusions upon AlF treatment.

  (A) HeLa cells that had been transfected with either Arf6 or Arf6N48R were treated with 30mM NaF and 50 μM AlCl₃ for 30 min, then fixed and stained for Arf6. Cells expressing Arf6 were also pretreated with 0.3% 1-butanol or 0.3 % 2-butanol for 10 min before AlF addition (B) Cells displaying protrusions are shown as a percentage of 100 transfected cells counted. Results shown are means plus standard error from two experiments. Bars, 10 μm.