F-BAR domain only protein 1

Functions in an early step of clathrin-mediated endocytosis. Has both a membrane binding/bending activity and the ability to recruit proteins essential to the formation of functional clathrin-coated pits. May regulate Bmp signaling by regulating clathrin-mediated endocytosis of Bmp receptors. Involved in the regulation of T-cell poliferation and activation. Affects TCR clustering upon receptor triggering and modulates its internalisation, playing a role in TCR-dependent T-cell activation.