(d) PtdIns(3) Pdepletion inhibits Golgi-to-ER retrograde transport of VSVG-KDELR. HeLa cells were transfected with empty vector, wild-type MTMR3, the C413S mutant of MTMR3, or treated with wortmannin or rapamycin, and then the ER pattern of VSVG-KDELR was quantified. UT, untreated. Data are the mean±s.d.; n = 100 cells for each group obtained from three independent experiments; **P0.01. 