Fig 1: iMer is expressed in gastrointestinal, genitourinary, endocrine, and lymphatic tissues, and inhibits phosphorylation of MERTK induced by GAS6. (A) iMer and full-length MERTK transcripts were detected by reverse transcription PCR, with G3PDH as loading control, from C57BL/6 wild-type mouse tissue. (B) A total of 697 cells treated with vehicle control or with iMer for 10 or 20 minutes as indicated were cultured with or without 200 nM GAS6 to activate MERTK receptor. MERTK was then immunoprecipitated. Phosphorylated (denoted by p-MERTK) and total MERTK proteins were detected by immunoblot. Images shown are representative of 2 independent experiments. (C) Mer isoform prevalence in platelets varies among individuals. Immunoblot of platelet lysates collected from 3 donors, 1 of whom had multiple samples collected across different days. The blots demonstrate full-length MERTK (cMer), soluble MERTK extracellular domain (sMer), and iMer. G3PDH, glyceraldehyde-3-phosphate dehydrogenase.