Could play a role in nuclear morphology, specifically nuclear size. H2O + NAD(+) = ADP-D-ribose + H(+) + nicotinamide Forms homomers. Interacts with SUN1, SUN2, SUN3, SUN4 and SUN5. The KASH domain, which contains a transmembrane domain, mediates the nuclear envelope targeting and is involved in the binding to the SUN proteins. The TIR domain mediates NAD(+) hydrolase (NADase) activity. Self-association of TIR domains is required for NADase activity. Shorter roots.