Figure 5: Proximity proteomes of the cardiac Z-disk and cardiac dyad.

(A-B) Schematics illustrating the foci of published proteomic mapping studies located at the Z-disk (A) and the overlying sarcolemma (B). (C) Overlapping proteomic mapping of sarcolemmal and Z-disk protein neighborhoods. Proteins included were described by authors as showing significant enrichment in the neighborhood of their protein of interest. In vivo proximity labeling occurred in knock-in mice with BioID fused to Ttn, BioID2 fused to Jph2, human iPSC-derived cardiac myocytes with knock-in of BioID fused to ACTN2. Live in-situ ex-vivo proximity labeling was examined in mice with inducible transgenic overexpression of the Ca_V1.2 α_1C subunit fused to APEX2. (D) Enrichment of proteins critical for cell structure, Ca²⁺ homeostasis, contraction and signaling were noted across multiple proximity proteomes, including those from isolated myocytes from mice overexpressing Ca_V1.2 β_2B-APEX2. Created in part with LucidChart and Biorender.com ^{14, 41, 42, 56}.