14 January 2015
Vol 7, Issue 270

About The Cover

Cover image expansion

ONLINE COVER A Tiny Bit of Titin. An inactive kinase—one of 244 domains in this giant protein—from the carboxyl-terminal region of titin, a mammoth muscle protein thought to be the largest in existence. Integral to muscle structure and function, titin helps give muscle its elasticity Roberts et al. show that when titin's carboxyl-terminal region harbors a mutation, it often causes serious heart disease. Mutations at the other, amino-terminal end of titin tend to be innocuous and are found in many perfectly healthy people. [CREDIT: C. BICKEL/SCIENCE TRANSLATIONAL MEDICINE]