STIM1 is a MT-plus-end-tracking protein involved in remodeling of the ER

Curr Biol. 2008 Feb 12;18(3):177-82. doi: 10.1016/j.cub.2007.12.050. Epub 2008 Jan 31.


Stromal interaction molecule 1 (STIM1) is a transmembrane protein that is essential for store-operated Ca(2+) entry, a process of extracellular Ca(2+) influx in response to the depletion of Ca(2+) stores in the endoplasmic reticulum (ER) (reviewed in [1-4]). STIM1 localizes predominantly to the ER; upon Ca(2+) release from the ER, STIM1 translocates to the ER-plasma membrane junctions and activates Ca(2+) channels (reviewed in [1-4]). Here, we show that STIM1 directly binds to the microtubule-plus-end-tracking protein EB1 and forms EB1-dependent comet-like accumulations at the sites where polymerizing microtubule ends come in contact with the ER network. Therefore, the previously observed tubulovesicular motility of GFP-STIM1 [5] is not a motor-based movement but a traveling wave of diffusion-dependent STIM1 concentration in the ER membrane. STIM1 overexpression strongly stimulates ER extension occurring through the microtubule "tip attachment complex" (TAC) mechanism [6, 7], a process whereby an ER tubule attaches to and elongates together with the EB1-positive end of a growing microtubule. Depletion of STIM1 and EB1 decreases TAC-dependent ER protrusion, indicating that microtubule growth-dependent concentration of STIM1 in the ER membrane plays a role in ER remodeling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / metabolism
  • Endoplasmic Reticulum / metabolism*
  • Gene Expression Regulation
  • HeLa Cells
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Microtubule-Associated Proteins / metabolism
  • Microtubules / metabolism*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Stromal Interaction Molecule 1


  • MAPRE1 protein, human
  • Membrane Proteins
  • Microtubule-Associated Proteins
  • Neoplasm Proteins
  • STIM1 protein, human
  • Stromal Interaction Molecule 1
  • Calcium