Biochemical and NMR studies reveal specific interaction between STIMATE C-tail and PI(4,5)P2 or PI(3,4,5)P3-containing membrane

STIMATE is an endoplasmic reticulum (ER) resident membrane protein that plays key roles in regulating calcium signaling occurring at ER-plasma membrane (PM) junctions. It is also involved in the regulation of ER-PM junction maintenance. STIMATE contains multiple putative transmembrane domains with a polybasic C tail (STIMATE-CT) that directly interacts with stromal interaction molecule 1 (STIM1) to promote STIM1 conformational switch. Here using liposome pulldown assay, we show that STIMATE-CT can specifically interact with PI(4,5)P-2 or PI(3,4,5)P-3 -containing membrane. NMR analysis indicates that STIMATE-CT is intrinsically disordered. Furthermore, NMR titration with bicelles and mutation analysis reveal that the regions of (VRYR245)-V-242 and (KKKK287)-K-284 in STIMATE-CT are both essential for its membrane binding. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

STIMATE is an ER resident membrane protein that regulates calcium signaling and ER-PM junction maintenance by interacting with STIM1. It can interact with membranes containing specific lipid components, and its intrinsic disorder and specific amino acid sequences are essential for membrane binding.