Figure 2: Ankyrin membrane domain specialization in myocytes. (A) Costameres: an interaction between ankyrin-B and ß2-spectrin recruits and retains dystrophin, ß-dystroglycan (DG), and microtubules to the sarcolemma. The retention of dystrophin and ß-dystroglycan specifically at costameres is dependent on direct interactions with ankyrin-G. Truncated ankyrin-G isoforms (AnkG107) are also expressed at costameres through interactions with plectin and filamin. (B) Intercalated disc: Ankyrin-G interacts with components of the gap junction (connexin43, Cx43) and desmosomal complex (plakophilin-2, Pkp). Other desmosomal components: desmoglein-2 (Dsg2), desmocollin-2 (Dsc2), and plakoglobin (Pkg). Ankyrin-G targets and scaffolds NaV1.5 at the ICD where it forms a local signaling complex with b4-spectrin and Ca2+/calmodulin kinase II (CaMKII). (C) T-tubule: Ankyrin-B targets and retains the sodium/calcium exchanger (NCX), sodium/potassium pump (NKA), and inositol triphosphate receptor (IP3R) at T-tubules of ventricular myocytes. The functional coupling of the sarcolemmal (SL) dihydropyridine receptor (DHPR) and ryanodine receptor (RyR) in the sarcoplasmic reticulum (SR) propagates calcium-induced calcium release. Ankyrin-G retains a subpopulation of voltage-gated sodium channels (NaV) at the T-tubules.