Negative regulator of the Notch signaling pathway, acting to restrict the activity of Notch to the dorsoventral (D/V) boundary of the wing imaginal disk. Also causes negative regulation of Notch during vein, eye, and bristle development. Acts by targeting Notch for endosomal degradation or recycling. Expressed in wing and eye imaginal disks. Flies exhibit problems in vein, eye, and bristle development. Belongs to the CC2D1 family.