Translocation of STIM1 and STIM2 from the endoplasmic reticulum to the plasma membrane is a key step in store-operated calcium entry in the cell. We show by isothermal titration calorimetry that calmodulin binds in a calcium-dependent manner to the polybasic C-termini of STIM1 and STIM2, a region critical for their translocation to the plasma membrane ( K D < or = 1 microM in calcium). HSQC NMR spectroscopy shows this interaction is in the fast exchange regime. By binding STIM1 and STIM2, calmodulin may regulate store refilling, thereby ensuring the maintenance of its own action in intracellular signaling.
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Sci Rep
January 2025
Laboratory of Biomedical Imaging and Data Analysis, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, St. Petersburg, Russia, 194021.
One of the mechanisms of calcium signalling in neurons is store-operated calcium entry (SOCE), which is activated when the calcium concentration in the smooth endoplasmic reticulum (ER) decreases and its protein-calcium sensor STIM (stromal interacting molecule) relocate to the endoplasmic reticulum and plasma membrane junctions, forms clusters and induces calcium entry. In electrically non-excitable cells, STIM1 is coupled with the positive end of a tubulin microtubule through interaction with EB1 (end-binding) protein, which controls its oligomerization, SOCE and participates in ER movement. STIM2 homologue, which is specific for mature hippocampal dendritic spines, is known to interact with EB3 protein, however, not much is known about the role of this interaction in STIM2 clustering or ER trafficking in neurons.
View Article and Find Full Text PDFSci Transl Med
December 2024
Department of Pathology, New York University Grossman School of Medicine, New York, NY 10016, USA.
Sjögren's disease (SjD) is an autoimmune disorder characterized by progressive salivary and lacrimal gland dysfunction, inflammation, and destruction, as well as extraglandular manifestations. SjD is associated with autoreactive B and T cells, but its pathophysiology remains incompletely understood. Abnormalities in regulatory T (T) cells occur in several autoimmune diseases, but their role in SjD is ambiguous.
View Article and Find Full Text PDFAnnu Rev Physiol
November 2024
Department of Pharmacology, Northwestern Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; email:
Store-operated Ca2+ entry (SOCE) is a widespread mechanism of cellular Ca2+ signaling that arises from Ca2+ influx across the plasma membrane through the Orai family of calcium channels in response to depletion of intracellular Ca2+ stores. Orai channels are a crucial Ca2+ entry mechanism in both neurons and glia and are activated by a unique inside-out gating process involving interactions with the endoplasmic reticulum Ca2+ sensors, STIM1 and STIM2. Recent evidence indicates that SOCE is broadly found across all areas of the nervous system where its physiology and pathophysiology is only now beginning to be understood.
View Article and Find Full Text PDFKorean J Physiol Pharmacol
January 2025
Department of Physiology, Yonsei University Wonju College of Medicine, Wonju 26426, Korea.
Renal cell carcinoma (RCC) presents significant clinical challenges, highlighting the importance of understanding its molecular mechanisms. While store-operated Ca entry (SOCE) is known to play an essential role in tumorigenesis and metastasis, its specific implications across various RCC subtypes remain underexplored. This study analyzed SOCE-related mRNA profiles from the KIRC and KIRP projects in The Cancer Genome Atlas (TCGA) database, focusing on differential gene expression and overall survival outcomes.
View Article and Find Full Text PDFFunction (Oxf)
October 2024
Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA.
Ca2+ signaling via the store operated Ca2+ entry (SOCE) mediated by STIM1 and STIM2 proteins and the ORAI1 Ca2+ channel is important in saliva fluid secretion and has been associated with Sjogren's disease (SjD). However, there are no studies addressing STIM1/2 dysfunction in salivary glands or SjD in animal models. We report that mice lacking Stim1 and Stim2 (Stim1/2K14Cre(+)) in salivary glands exhibited reduced Ca2+ levels and hyposalivate.
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