Optogenetic control of chemokine secretion. (A) Construct design for optogenetic triggering of murine Cxcl2. (B) Distribution of Cxcl2-YFP-2xUVR8 before or after PA with 9 mJ. Scale bar = 20 µm. (C) Detection of cleaved Cxcl2 in supernatants and uncleaved Cxcl2-YFP-2xUVR8 in lysates from nontreated (no PA) or photo-activated cells with indicated doses of UVB. Supernatant samples were treated with PNGase to obtain single bands representing nonglycosylated chemokine. (D) Quantification of protein in the supernatant samples shown in panel C, based on band intensity, normalized against the lysate bands and relative to the “no PA” condition. (E) Time course of cleaved Cxcl2 secretion. Supernatants were collected in 30-minute intervals, washing the cells between collection time points, to assess new chemokine production. (F) Quantification of exact protein amount shown in panel E. TM, transmembrane protein anchor.