![Figure 3. Atrial ECC: tandem RyR activation and FDUF mechanism. AP-induced Ca release from j-SR by LCC activation (1), followed by propagation through mitochondria-free transition zone (TZ; 2) and activation of centripetal propagating CICR (3) from central (CT) nj-SR CRUs (CT1→CT2→CT3→…). Inset: FDUF mechanism. Tandem RyR activation by cytosolic CICR (A) and luminal RyR sensitization (B) by elevated [Ca]SR (SR Ca sensitization signal) resulting in Ca release (C). SR Ca sensitization signal is generated by Ca uptake at the activation front by SERCA. Reproduced from Maxwell and Blatter (2017).](https://cdn.rupress.org/rup/content_public/journal/jgp/149/9/10.1085_jgp.201711809/6/jgp_201711809_fig3.jpeg?Expires=1767669834&Signature=0KRrBnad-K1jUKs-CNnhxY7kvzwjbYj0eQMDUSiDz~hUsuGuocoDYe0QKDb7Le4ByDrrd5sxdxMlbhOpUNhvFltHXZfW4DzS0B4Rife0pbN-spexGdyB5miTF-xF8XN1jaDh8k2O7z8myIczZyW77-8U5r5WWwBZHzD48CgtAk8GgzDk9Z4i3gM00crkR0f~vT6-DXkfTb2OvYm79Y~bGCCP30dKP4NSRoRpLt8hcIDQmXRxGE3aEV7UAYfEQ8JpI5tG7xnelkKTI-ZP2b7-mUpMYKKxcnLI3NSswABCPuhKvH4wNEcEhKlOPaiwhjsiKBbz88olTPqjOA4ClGCKow__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Figure 3.
Atrial ECC: tandem RyR activation and FDUF mechanism. AP-induced Ca release from j-SR by LCC activation (1), followed by propagation through mitochondria-free transition zone (TZ; 2) and activation of centripetal propagating CICR (3) from central (CT) nj-SR CRUs (CT1→CT2→CT3→…). Inset: FDUF mechanism. Tandem RyR activation by cytosolic CICR (A) and luminal RyR sensitization (B) by elevated [Ca]SR (SR Ca sensitization signal) resulting in Ca release (C). SR Ca sensitization signal is generated by Ca uptake at the activation front by SERCA. Reproduced from Maxwell and Blatter (2017).
