FIG. 9.

Model of SUN1 topology and interactions at the NE. SUN1 is anchored at the INM through interaction of the nucleoplasmic NTD with lamin A and other nuclear factors, most likely chromatin (indicated by the question mark). The CTD of SUN1 lies in the NE lumen, where it interacts with nesprins that contain a C-terminal membrane-spanning KASH domain, resulting in their anchoring at the ONM. The N terminus of long nesprin isoforms binds to actin. As a result, a direct physical connection between the nuclear interior and the actin cytoskeleton is created. NPC, nuclear pore complex; CH, calponin homology domain.