(A) Actinin-BirA* was expressed, via CRISPR knock-in, in human inducible pluripotent stem cell derived cardiomyocytes. Biotinylated proteins were purified and identified by mass spectrometry. Gene ontology analysis of the proteins revealed functions in actin cytoskeleton, sarcomere, and RNA binding. The light-green shading indicates an estimate of the zone of biotinylation. (B) RNA precipitation followed by sequencing (RIP-seq) using streptavidin affinity purification to pull-down RNA-binding proteins that were biotinylated within ~10 nm of actinin-BirA*. Gene ontology analysis indicated enrichment of oxidative phosphorylation (OXPHOS) transcripts. (C) Actinin interacts directly with insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), localizing IGF2BP2 to Z-disks. Adapted from 56.