Another micropeptide flexes its muscle

Genome annotation is a complex but imperfect art. Attesting to its limitations is the growing evidence that certain transcripts annotated as long noncoding RNAs (lncRNAs) in fact code for small peptides with biologically important functions. One such lncRNA-derived micropeptide in mammals is myoregulin, which reduces muscle performance by inhibiting the activity of a key calcium pump. Nelson et al. describe the opposite activity in a second lncRNA-derived micropeptide in mammalian muscle, called DWORF (see the Perspective by Payre and Desplan). This peptide enhances muscle performance by activating the same calcium pump. DWORF may prove to be useful in improving the cardiac muscle function of mammals with heart disease.

Science, this issue p. 271; see also p. 226