Figure 3.

C2 Domains of Tcb3 Are Required to Form ER-medial-Golgi Contact

(A) Wild-type and tcb1Δ2Δ3Δ cells expressing mRFP-Gos1 (medial-Golgi marker) and Kar2-ss-GFP (ER marker) were grown at 25°C and imaged by DIC and fluorescence microscopy. Scale bar, 5 μm. The total number of mRFP-Gos1 puncta in 100 cells was quantified. The number of mRFP-Gos1 puncta associated with ER (cER or nER), cER, or nER was also quantified, and the results were expressed as percentage to the total number of mRFP-Gos1 puncta. Experiments were repeated three times; n = 300 cells. The data represent means ± SD of three experiments. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.005 by Student's t-test. n.s., not significant.

(B) tcb3Δ cells expressing mRFP-Gos1 (medial-Golgi marker) and Kar2-ss-GFP (ER marker) with empty, TCB3, TCB3(ΔSMP), TCB3(ΔC2), or TCB3(ΔSMP-C2) plasmid were grown at 25°C and imaged by DIC and fluorescence microscopy. Scale bar, 5 μm. The total number of mRFP-Gos1 puncta and the number of mRFP-Gos1 associated with the ER were quantified as described in (A), and the data represent means ± SD of three independent experiments. ∗p < 0.05 by Student's t-test. n.s., not significant.