Missense mutation in immunodeficient patients shows the multifunctional roles of coiled-coil domain 3 (CC3) in STIM1 activation.
Store-operated Ca(2+) entry (SOCE) is a universal Ca(2+) influx pathway that is important for the function of many cell types. SOCE occurs upon depletion of endoplasmic reticulum (ER) Ca(2+) stores and relies on a complex molecular interplay between the plasma membrane (PM) Ca(2+) channel ORAI1 and the ER Ca(2+) sensor stromal interaction molecule (STIM) 1. Patients with null mutations in ORAI1 or STIM1 genes present with severe combined immunodeficiency (SCID)-like disease. Here, we describe the molecular mechanisms by which a loss-of-function STIM1 mutation (R429C) in human patients abolishes SOCE. R429 is located in the third coiled-coil (CC3) domain of the cytoplasmic C terminus of STIM1. Mutation of R429 destabilizes the CC3 structure and alters the conformation of the STIM1 C terminus, thereby releasing a polybasic domain that promotes STIM1 recruitment to ER-PM junctions. However, the mutation also impairs cytoplasmic STIM1 oligomerization and abolishes STIM1-ORAI1 interactions. Thus, despite its constitutive localization at ER-PM junctions, mutant STIM1 fails to activate SOCE. Our results demonstrate multifunctional roles of the CC3 domain in regulating intra- and intermolecular STIM1 interactions that control (i) transition of STIM1 from a quiescent to an active conformational state, (ii) cytoplasmic STIM1 oligomerization, and (iii) STIM1-ORAI1 binding required for ORAI1 activation.
Department of Pathology, New York University School of Medicine, New York, NY 10016;
Mate
M
Maus
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611;
Amit
A
Jairaman
Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, M5G 1L7; Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada, N6A 5C1;
Peter B
PB
Stathopulos
Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria;
Martin
M
Muik
Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria;
Marc
M
Fahrner
Department of Pathology, New York University School of Medicine, New York, NY 10016;
Carl
C
Weidinger
Department of Pathology, New York University School of Medicine, New York, NY 10016;
Melina
M
Benson
Center for Chronic Immunodeficiency, University Medical Center, University of Freiburg, D-79106 Freiburg, Germany; Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; and.
Sebastian
S
Fuchs
Center for Chronic Immunodeficiency, University Medical Center, University of Freiburg, D-79106 Freiburg, Germany; Center for Pediatrics and Adolescent Medicine, University Medical Center, University of Freiburg, D-79106 Freiburg, Germany.
Stephan
S
Ehl
Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria;
Christoph
C
Romanin
Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, M5G 1L7;
Mitsuhiko
M
Ikura
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611;
Murali
M
Prakriya
Department of Pathology, New York University School of Medicine, New York, NY 10016; feskes01@nyumc.org.
Stefan
S
Feske
D002118:Calcium / Q000737:chemistry; D015220:Calcium Channels / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D019281:Dimerization; D004721:Endoplasmic Reticulum / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D005808:Genes, Recessive; D057809:HEK293 Cells; D006720:Homozygote; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000235:genetics*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics*; D018613:Microscopy, Confocal; D020125:Mutation, Missense; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000235:genetics*; D000071740:ORAI1 Protein; D017434:Protein Structure, Tertiary; D000071737:Stromal Interaction Molecule 1
D015220:Calcium Channels; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; D002118:Calcium
ORAI1; STIM1; calcium; immunodeficiency; mutation