Ca2+/calmodulin-dependent protein kinase II β (CaMKIIβ) decodes ER Ca2+ transients to trigger autophagosome formation. Qiaoxia Zheng et al.

These are unprocessed and uncompressed imaging data (microscopy as well as gels and blots) of the study "Ca2+/calmodulin-dependent protein kinase II β (CaMKIIβ) decodes ER Ca2+ transients to trigger autophagosome formation". In this study, we focused on how Ca2+ transients on the ER outer surface elicited by autophagy stimuli are sustained and decoded to trigger autophagosome formation in multicellular organisms. Here we show that CaMKIIβ integrates ER Ca2+ transients to trigger liquid-liquid phase separation (LLPS) of the autophagosome-initiating FIP200 complex. In response to ER Ca2+ transients, CaMKIIβ is recruited from actin filaments and forms condensates, which serve as sites for emergence of or interaction with FIP200 puncta. CaMKIIβ phosphorylates FIP200 at Thr269, Thr1127 and Ser1484 to modulate LLPS and properties of the FIP200 complex, thereby controlling its function in autophagosome formation. CaMKIIβ also controls the amplitude, duration and propagation of ER Ca2+ transients during autophagy induction. CaMKIIβ mutations identified in the neurodevelopmental disorder MRD54 affect the function of CaMKIIβ in autophagy. Our study reveals that CaMKIIβ is essential for sustaining and decoding ER Ca2+ transients to specify autophagosome formation in metazoans.