Characterization of GPR84 phospho-site-specific antisera. Flp-In TREx 293 cells harboring human GPR84-eYFP (-dox) or induced to express the receptor construct (+dox) were treated with Lambda protein phosphatase (λ-PPase), 2-HTP, and/or compound 101 (cmp101) as indicated. Following enrichment of the receptor construct via GFP-trapping and SDS-PAGE immunoblots were performed with the C-terminal GPR84 structural antiserum (A and D) or the phospho-site-targeted antisera pSer221/pSer224 (B and E), and pThr263/pThr264 (C and F). Apparent molecular mass markers are shown, and mature and immature forms of GPR84 are highlighted. Illustrative outcomes are displayed. dox, doxycycline.