Fig. 2.
FGF13 associates with cavin protein complexes in caveolin-rich lipid rafts of cardiomyocytes. (A) Schematic of the cavin–caveolin complex at a sarcolemmal caveola. Cavin complexes are assembled in the cytoplasm before being recruited to caveolae. Mass spectrometry analysis of immunoprecipitated FGF13 complex identified 17 unique peptides across cavin 1, cavin 2, and cavin 4 (detailed peptide information in Table S4). (B) Western blots of sucrose density fractions 2–11 from adult ventricular myocytes showed FGF13 cofractionating with cavin 1, caveolin 3, sodium channel (NaV), and junctophilin-2 (JPH2) in lipid raft fractions (3–5). Fraction 1 is not shown because no protein is present in the first fraction. (C) FGF13 densitometry normalized to protein concentration emphasizes its lipid raft enrichment.