Keeping it fresh: ribosomal protein SA sustains sarcomeric function via localized translation
Abigail Nagle, Michael Regnier, Jennifer Davis
Abigail Nagle, Michael Regnier, Jennifer Davis
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Commentary

Keeping it fresh: ribosomal protein SA sustains sarcomeric function via localized translation

Abstract

Mechanical stress from cardiomyocyte contraction causes misfolded sarcomeric protein replacement. Sarcomeric maintenance utilizes localized pools of mRNAs and translation machinery, yet the importance of localized translation remains unclear. In this issue of the JCI, Haddad et al. identify the Z-line as a critical site for localized translation of sarcomeric proteins, mediated by ribosomal protein SA (RPSA). RPSA localized ribosomes at Z-lines and was trafficked via microtubules. Cardiomyocyte-specific loss of RPSA in mice resulted in mislocalized protein translation and caused structural dilation from myocyte atrophy. These findings demonstrate the necessity of RPSA-dependent spatially localized translation for sarcomere maintenance and cardiac structure and function.

Authors

Abigail Nagle, Michael Regnier, Jennifer Davis

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Figure 1

RPSA is important for maintenance of cardiac cells and heart tissue.

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RPSA is important for maintenance of cardiac cells and heart tissue. (A)...
(A) RPSA serves as an essential component for localized protein translation within the sarcomere. It localizes to the Z-line where it is involved with tethering ribosomes to Z-lines within myofibrils. RPSA depends on the microtubule network for its localization to the ribosomes. Structurally, the C-terminus of RPSA associates with the α-actinin–containing Z line while the N-terminus interacts with the ribosome. (B) Local translation at the Z-lines is important for protein replacement within the sarcomere and for maintaining myofibril integrity. Loss of RPSA leads to loss of sarcomeric protein translation, loss of ordered sarcomere structure, and myocyte atrophy.