SS18L1 and hydrops fetalis: CaMKII is involved in a variety of cellular processes, including cell growth or hypertrophy,51 and it has been proposed as a good candidate for HF treatments.21 We demonstrate that CaMKII in the close environment of the β2AR-LTCC complex plays a crucial role, which could be exacerbated in the Crest domains of MI cells, in which the pathologically active LTCC can be controlled by blocking CaMKII (Figure S4).