Interaction between emerin and nuclear lamins

Emerin is an inner nuclear membrane protein that is involved in X-linked re cessive Emery-Dreifuss muscular dystrophy (X-EDMD). Although the function o f this protein is still unknown, we revealed that C-terminus transmembrane domain-truncated emerin (amino acid 1-225) binds to lamin A with higher aff inity than lamin C. Screening for the emerin binding protein and immunoprec ipitation analysis showed that lamin A binds to emerin specifically. We als o used the yeast two-hybrid system to clarify that this interaction require s the top half of the tail domain (amino acid 384-566) of lamin A. Lamin A and lamin C are alternative splicing products of the lamin A/C gene that is responsible for autosomal dominant Emery-Dreifuss muscular dystrophy (AD-E DMD). These results indicate that the emerin-lamin interaction requires the tail domains of lamin A and lamin C. The data also suggest that the lamin A-specific region (amino acids 567-664) plays some indirect role in the dif ference in emerin-binding capacity between lamin A and lamin C. This is the first report that refers the difference between lamin A and lamin C in the interaction with emerin. These data also suggest that lamin A is important for nuclear membrane integrity.