From the Cover: STIM1-induced precortical and cortical subdomains of the endoplasmic reticulum.
Store-operated calcium entry relies on the formation of a specialized compartment derived from the endoplasmic reticulum (ER) and closely apposed to the plasma membrane. In this study, detailed ultrastructural analysis revealed the existence of three distinct structures derived from conventional ER: precortical ER, cortical ER, and thin cortical ER. Precortical subdomains of the ER enriched in STIM1 can form without contacting the plasma membrane. Upon ER calcium depletion, these subdomains are translocated to the plasma membrane to form cortical ER, which is still connected to the conventional ER. Thin cortical ER, depleted of BiP and deprived of attached ribosomes, may represent a specialized region dedicated to calcium regulation and not engaged in protein translocation and folding. These observations form the basis for future structure-function analysis of cortical ER.
Orci
Lelio
L
Department of Cell Physiology and Metabolism, University of Geneva Medical School, 1211 Geneva 4, Switzerland. lelio.orci@unige.ch
Ravazzola
Mariella
M
Le Coadic
Marion
M
Shen
Wei-Wei
WW
Demaurex
Nicolas
N
Cosson
Pierre
P
D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D000071737:Stromal Interaction Molecule 1
D008565:Membrane Proteins; D009363:Neoplasm Proteins; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; D002118:Calcium