Figure 5. Calcium handling genes that undergo alternative splicing transitions in postnatal skeletal muscle development.

Diagram of calcium handling genes that are expressed in skeletal muscle. Genes with 15% or greater ΔPSI from PN2 to PN28 are underlined and include members of several calcium channels: NCX (sodium calcium exchanger), PMCA (plasma membrane Ca²⁺-ATPase), SERCA (sarco/endoplasmic reticulum Ca²⁺-ATPase), and RYR (ryanodine receptor); triadin (Trdn) which associates with Ryr1, junctin (Asph) and FKBP12 (Fkbp1a). Signaling cascades that are affected by alternative splicing include Ca²⁺/camodulin (CaM)-dependent calcineurin (CaN) and calmodulin-dependent protein kinase II (CamkII) along with the downstream transcription factor NFATC. NFATC and transcription factors (TFs) regulated by CamkII activate genes for hypertrophy and fiber type specification.