Actinin BioID reveals sarcomere crosstalk with oxidative metabolism through interactions with IGF2BP2

• Published in: Cell reports (Cambridge) Vol. 36; no. 6; p. 109512
• Main Authors: Ladha, Feria A., Thakar, Ketan, Pettinato, Anthony M., Legere, Nicholas, Ghahremani, Shahnaz, Cohn, Rachel, Romano, Robert, Meredith, Emily, Chen, Yu-Sheng, Hinson, J. Travis
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 10.08.2021; Elsevier
• Subjects: actinin; Actinin - metabolism; BioID; Cardiomyopathy, Hypertrophic - physiopathology; Electron Transport; HEK293 Cells; Humans; IGF2BP2; mRNA localization; Muscle Contraction; Oxidation-Reduction; oxidative phosphorylation; Protein Binding; Protein Interaction Mapping; protein-protein interactions; quantitative proteomics; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-binding proteins; RNA-Binding Proteins - metabolism; sarcomere; Sarcomeres - metabolism; Z-disc; BioID; mRNA localization; Z-disc; RNA-binding proteins; IGF2BP2; actinin; sarcomere; quantitative proteomics; oxidative phosphorylation; protein-protein interactions
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2021.109512

Actinins are strain-sensing actin cross-linkers that are ubiquitously expressed and harbor mutations in human diseases. We utilize CRISPR, pluripotent stem cells, and BioID to study actinin interactomes in human cardiomyocytes. We identify 324 actinin proximity partners, including those that are dependent on sarcomere assembly. We confirm 19 known interactors and identify a network of RNA-binding proteins, including those with RNA localization functions. In vivo and biochemical interaction studies support that IGF2BP2 localizes electron transport chain transcripts to actinin neighborhoods through interactions between its K homology (KH) domain and actinin’s rod domain. We combine alanine scanning mutagenesis and metabolic assays to disrupt and functionally interrogate actinin-IGF2BP2 interactions, which reveal an essential role in metabolic responses to pathological sarcomere activation using a hypertrophic cardiomyopathy model. This study expands our functional knowledge of actinin, uncovers sarcomere interaction partners, and reveals sarcomere crosstalk with IGF2BP2 for metabolic adaptation relevant to human disease. [Display omitted] •BioID identifies 324 actinin proximity partners through sarcomere assembly•IGF2BP2 directly binds actinin’s rod domain through its KH domain•IGF2BP2-actinin interactions determine ETC transcript localization•Actinin-IGF2BP2 interactions regulate metabolic adaptation to sarcomere function Ladha et al. combine BioID, human cardiomyocytes, and CRISPR-Cas9 to interrogate the actinin interactome. This reveals 324 actinin proximity partners, including RNA-binding proteins that bind transcripts encoding ETC functional components. Among these RNA-binding proteins, IGF2BP2 directly binds actinin, and actinin-IGF2BP2 interactions regulate ETC transcript localization and metabolic adaptation to sarcomere function.