The Breakdown of Barriers in Old Cells May Hold Clues to Aging Process (image) Salk Institute Share Print E-Mail Caption In aging cells one of the proteins composing nuclear pores becomes damaged and molecules that should be restricted to the cytoplasm invade the nucleus (outline shown in red). In particular, a protein called tubulin (shown in green), which is strictly a cytoplasmic protein, shows up as long filaments that co-opt a large part of the nucleus. Credit Courtesy of Dr. Maximiliano D'Angelo, Salk Institute for Biological Studies. Usage Restrictions News media reproduction to illustrate this story permitted with proper attribution as provided above. For one time use only. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.