Recruitment of effector proteins by micropatterned IFNAR. (a) Constitutive binding of STAT2 to micropatterned Halo-IFNAR2: HeLa cells transfected with HaloTag-IFNAR2 and STAT2-EGFP (green channel). IFNAR2 micropatterning was confirmed by staining with ^AT655IFNα2 (red channel). Cell boundaries are indicated by dotted lines. Bars, 10 µm. (b) Dynamics of the STAT2 interaction with micropatterned IFNAR2 probed by FRAP (representative of 10 cells analyzed). (left) FRAP curves inside and outside the IFNAR2 micropattern. (right) Corrected FRAP curve and fit of a monoexponential function. (c) Recruitment of STAT1 to IFNAR2 via STAT2: HeLa cells expressing HaloTag-IFNAR2, STAT1-EGFP (green channel), and STAT2-TagRFP (yellow channel). After image acquisition, IFNAR2 patterning was confirmed by incubation of ^AT655IFNα2 (red channel). Cell boundaries are indicated by dotted lines. Bars, 10 µm. (d) Profiles of sectional distribution of fluorescence intensity in each channel in c (representative of six cells analyzed). Integrated line profiles were scaled to a similar amplitude and overlaid at an arbitrary ordinate scale. a.u., arbitrary unit.