Identification of PTX2 as a potential partner for FX. THP1-derived macrophage lysate was incubated with (main sample) or without (control) FX for 1 hour. FX was immunoprecipitated, and the collected material was analyzed for identification of potential FX partners using nano-HPLC separation and Orbitrap sequencing of the different peptides (A). Data were processed through the MASCOT algorithm to identify peptides and corresponding proteins. Positive candidates were proteins not detected in the control sample and detected in the FX-incubated sample with a MASCOT detection score >100 in 2 different experiments (B). (C) THP1-derived macrophages were immunostained for FX (red), PTX2 (blue), and SR-AI (green), and representative images were acquired in confocal microscopy. Arrows indicate area of triple colocalization. Bar represents 10 µm; objective 63×, z-depth 1 µm.