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. Author manuscript; available in PMC: 2009 Sep 6.
Published in final edited form as: Cell. 2009 Feb 26;136(5):876–890. doi: 10.1016/j.cell.2009.02.014

Figure 1. Deletion of the STIM1 Polybasic Domain Distinguishes Orai1-dependent and independent Mechanisms of STIM1 Accumulation at ER-PM Junctions.

Figure 1

(A) Wild-type mCh-STIM1 expressed alone in HEK 293 cells redistributes from a diffuse ER distribution (Rest) to the cell periphery after store depletion with TG (0 Ca + TG). After depletion, puncta are visible at the cell footprint. (B) eGFP-myc-Orai1 when expressed alone does not redistribute into puncta after depletion. (C) When expressed together, STIM1 and Orai1 form colocalized puncta after store depletion. (D) Unlike wild-type STIM1, STIM1-ΔK expressed alone fails to form puncta; however, when coexpressed with Orai1 both proteins form colocalized puncta after store depletion (E). (F) Store depletion activates ICRAC in HEK 293 cells expressing STIM1-ΔK and Orai1 demonstrating that the polybasic region is not essential for ICRAC activation. All images were taken of cell footprints using confocal microscopy. Scale bars, 10 μm.