Scheme 1. Regulation of IGF1R endocytosis and recycling by two potential pathways.
Based on our findings we propose two alternate pathways leading to IGF1R internalization and subsequent recycling: (1) Clathrin-associated, flotillin-mediated endocytosis results in fast internalization and recycling of IGF1R; and (2) Clathrin-associated, adaptor-related protein complex 2-mediated endocytosis promotes slower IGF1R internalization and recycling.