PROTEOLYSIS OF ANKYRIN AND NA+ K+-ATPASE IN POSTMORTEM RAT-BRAIN - ISCALPAIN INVOLVED/

Ankyrin links the fodrin-based cytoskeleton to membrane proteins such as Na+/K+-ATPase, thereby maintaining cellular integrity. Immunoblotti ng by antibody raised against erythrocyte ankyrin demonstrated the pro teolysis of ankyrin, which was highly correlated with postmortem inter val (0-24 h). Proteolysis in the postmortem brain generated the 160-kD a fragment with an identical size as the fragment formed after in vitr o proteolysis by calpain. Although mu M Ca2+ induced the proteolysis i n the homogenate, the presence of mu-calpain was not demonstrated by i mmunoblotting using the antibody that reacts with large subunits both of mu- and m-calpains. Na+/K+-ATPase was also proteolyzed in the postm ortem brain. (C) 1997 Elsevier Science Ireland Ltd.