Adaptor protein GULP is involved in stabilin-1-mediated phagocytosis

The clearance of apoptotic cells is critical during cellular homeostasis as well as inflammation resolution. Recently, we found that stabilin-1 is a phagocytic receptor that is involved in the clearance of apoptotic cells. However, the downstream signaling pathway of stabilin-1-mediated phagocytosis remains to be investigated. Here we identify that GULP is able to specifically interact with the NPxF/Y motif of stabilin-1 cytoplasmic region. The PTB domain of GULP is necessary for interaction with stabilin-1. GULP is enriched around PS-coated beads for phagocytosis and co-localized with stabilin-1. Downregulation of endogenous GULP expression decreased stabilin-1-mediated phagocytosis. Thus, these results indicate that GULP functions as an adaptor protein for stabilin-1-mediated phagocytosis.

Research highlights
► 1. GULP directly binds to NPxF motif of stabilin-1 C-terminal.
► 2. The PTB domain of GULP mediates its interaction with stabilin-1.
► 3. GULP and stabilin-1 are enriched around PS-coated beads for phagocytosis.
► 4. Downregulation of GULP decreased stabilin-1-mediated phagocytosis.