Phospho-Peptide Pull-Down Reveals Inhibitory Signaling Partners of CD200R1

Project Description (Revised): CD200R1 inhibits phagocytosis through its intracellular tyrosine residues Y286 and Y297. To investigate whether these residues recruit inhibitory molecules, we performed pull-down assays using synthetic peptides—either phosphorylated or unphosphorylated—corresponding to regions containing Y286 and Y297. These peptides were incubated with lysates from mouse bone marrow-derived macrophages (BMDMs), and interacting proteins were subsequently identified by mass spectrometry.