Stim (Drosophila melanogaster, P83094) notes

Identity

• Single fly STIM (stromal interaction molecule) orthologue; single-pass ER membrane protein with luminal EF-hand/SAM domain and cytosolic coiled-coil/SOAR region that gates Orai.

Evidence

• Roos et al. 2005 identified Stim in an S2-cell RNAi screen: PMID:15866891; PMID:15866891; EF hand proposed as sensor PMID:15866891. Note: Ca2+ binding was proposed from sequence, not measured directly in this paper.
• Stim-Orai co-IP enhanced by store depletion PMID:16921385.
• Stim C terminus gates Orai and drives Orai oligomerisation PMID:18820677.
• Development: PMID:18950512
• Neurons: Stim needed for flight PMID:19515818.
• ER-PM contacts at presynaptic terminals PMID:36952540.

Curation thoughts

• Plasma membrane annotations: STIM1 has a small PM pool in mammals, but fly Stim acts from ER at ER-PM junctions; PM IEA/NAS/IBA kept as non-core/over-annotation considered. Zhang 2006 NAS says "translocates to the plasma membrane" — mechanistically it is ER-PM junction, not PM insertion. Mark as over-annotated for NAS/IEA; IBA PM also over-annotated.
• calcium ion sensor activity (IMP) fits the EF-hand sensing role; accept.