Fig. 2.

A human platelet secretome and receptor protein microarray identifies FcεR1α as a ligand for PEAR1. Soluble recombinant biotinylated proteins representing the secretome and receptor repertoire of the human platelet were purified and arrayed in six 3-fold dilutions on streptavidin-coated slides. A, the array was screened with a control (rat Cd200) pentamerized FLAG-tagged prey that bound the background baits FcγR2α (red box) and P4HB (white box). B, PEAR1 prey additionally interacted with the FcεR1α bait (orange box) when compared with the control in A; fluorescence intensities are quantified in supplemental Fig. S4. C, FcεR1α prey additionally interacted with the PEAR1 bait (blue box) in comparison with the control. Note that the nine regularly spaced markers are orientation markers and that the boxed areas marked on the array enclose the location of the six spots containing the dilutions of the named immobilized baits (see supplemental Fig. S3).