Variety Upon Variety

Titin, the largest protein produced in the body, is a giant spring-like protein found in muscle cells, including those of the heart (pictured). There are multiple versions of titin, and their production is regulated, at least in part, by splicing factor (cutting the RNA transcript to make different sized versions of the same protein) RBM20 (coloured blue). In the infant mammalian heart, for example, most titin is long and elastic, while in older mammals RBM20 activity leads to shorter stiffer versions of the protein. Aberrant production of RBM20 has been linked to certain cardiomyopathies, suggesting its inhibition in these disorders could be clinically beneficial. Interestingly, new research in rodent and human samples reveals RBM20 itself also has multiple versions, and their production is influenced by developmental stage and disease. The findings suggest regulation of heart muscle flexibility is much more complex than previously thought and that any therapies targeting RBM20 might need fine tuning to pinpoint specific versions of the factor.

Written by Ruth Williams

Ruth Williams

Writer

Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

Website

• Image from work by Michael H. Radke, Victor Badillo Lisakowski and Stefan Meinke, and colleagues
• Translational Cardiology and Functional Genomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Nature Communications, May 2026