3TEQ: Crystal Structure Of Soar Domain

Calcium influx through the Ca(2+) release-activated Ca(2+) (CRAC) channel is an essential process in many types of cells. Upon store depletion, the calcium sensor in the endoplasmic reticulum, STIM1, activates Orai1, a CRAC channel in the plasma membrane. We have determined the structures of SOAR from Homo sapiens (hSOAR), which is part of STIM1 and is capable of constitutively activating Orai1, and the entire coiled coil region of STIM1 from Caenorhabditis elegans (ceSTIM1-CCR) in an inactive state. Our studies reveal that the formation of a SOAR dimer is necessary to activate the Orai1 channel. Mutations that disrupt SOAR dimerization or remove the cluster of positive residues abolish STIM1 activation of Orai1. We identified a possible inhibitory helix within the structure of ceSTIM1-CCR that tightly interacts with SOAR. Functional studies suggest that the inhibitory helix may keep the C-terminus of STIM1 in an inactive state. Our data allowed us to propose a model for STIM1 activation.
PDB ID: 3TEQDownload
MMDB ID: 98668
PDB Deposition Date: 2011/8/15
Updated in MMDB: 2013/07
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 3TEQ: dimeric; determined by author and by software (PISA)
Molecular Components in 3TEQ
Label Count Molecule
Proteins (2 molecules)
Stromal Interaction Molecule 1(Gene symbol: STIM1)
Molecule annotation
Chemicals (5 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB