3TER

Crystal structure of SOAR domain with Inhibition helix from C. elegans

Summary for 3TER

• Entry DOI: 10.2210/pdb3ter/pdb
• Descriptor: Mammalian stromal interaction molecule-1 (2 entities in total)
• Functional Keywords: dimer, metal binding protein
• Biological source: Caenorhabditis elegans (nematode)
• Total number of polymer chains: 2
• Total formula weight: 31233.69

Authors

Yang, X.,Jin, H.,Cai, X.,Shen, Y. (deposition date: 2011-08-15, release date: 2012-04-11, Last modification date: 2024-03-20)

Primary citation

Yang, X.,Jin, H.,Cai, X.,Li, S.,Shen, Y.
Structural and mechanistic insights into the activation of Stromal interaction molecule 1 (STIM1).
Proc.Natl.Acad.Sci.USA, 109:5657-5662, 2012

PubMed Abstract: 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.

PubMed: 22451904
DOI: 10.1073/pnas.1118947109

Experimental method

X-RAY DIFFRACTION (2.551 Å)