Complementary examples to Fig. 7 C ; MIM-Emerald rescue experiment and myosin localization in MIM ^ΔIBAR/+ . (A) Time-lapse sequence of representative LSVs from MIM^ΔIBAR/Def and I-BAR^OE SGs undergoing kiss-and-run (KAR) w/o and w actomyosin (SRRF intensity-projection). Complementary to Fig. 6 C. Top and middle: MIM^ΔIBAR/Def and I-BAR^OE; KAR w/o actomyosin. Consecutive fusion events on the same LSV at 00:00 and 08:47 and at 00:00 and 12:45 (asterisks). Bottom: I-BAR^OE; KAR w actomyosin. “Deforming LSV” (dashed line) eventually fused again at 05:36 (asterisk). Glue-GFP (green) and LifeAct-Ruby (magenta). (B) Mean frequency (%) of stalling, full collapse (FC), kiss-and-run (KAR), and membrane crumpling (MC) in WT, MIM^Null/Def, and MIM^ΔIBAR/Def using the Glue-GFP and LifeAct-Ruby markers and in MIM^+/Def, MIM^Null/Def, and MIM^ΔIBAR/Def expressing MIM-Emerald compared with WT glands using the Sqh-mCherry (myosin II light chain) marker from Fig. 6 A and Fig. 7 A (semi-transparent bars). The majority of fusion events observed in WT SGs with Glue-GFP and LifeAct-Ruby markers result in membrane crumpling events (67 ± 3%), MIM^Null/Def and MIM^ΔIBAR/Def SGs present the MIM loss-of-function phenotype and a high frequency of kiss-and-run events (49 ± 3% (****) and 68 ± 7% (****), respectively). WT SGs using the Sqh-mCherry marker do not significantly differ from the WT SGs using the Glue-GFP and LifeAct-Ruby markers. In MIM^+/Def SGs that also expressed MIM-Emerald, the mode of exocytosis distribution did not vary significantly from the WT SGs using the Sqh-mCherry assay. When MIM-Emerald is expressed in MIM^Null/Def or MIM^ΔIBAR/Def SGs, the loss-of-function phenotype is rescued, and membrane crumpling exocytosis is the major exocytosis mode observed (52 ± 5% (***) and 68 ± 3% (ns), respectively). N (SGs) ≥ 3, n (events) ≥ 150. P values for MIM^Null/Def: ***(MC) = 0.009667. Two-tailed unpaired multiple t tests corrected using the Holm-Sidak method. (C) Time-lapse sequence of representative LSVs from WT SGs undergoing membrane crumpling and MIM^ΔIBAR/+ SGs undergoing full collapse (also in Video 10; confocal intensity-projection). Fusion (white asterisks). Sqh-mCherry (green). Time in A and C, mm:ss; relative to fusion. UAS-based expression in I-BAR^OE (A) driven by c135-GAL4, in MIM^ΔIABR/Def (A) driven by fkh-GAL4, in B for the Glue-GFP and LifeAct-Ruby expressing SGs driven by fkh-GAL4 and for Sqh-mCherry expressing SGs driven by c135-GAL4. Scale bars in A and C, 1 µm.