Figure 7 - uploaded by Kenji Oritani
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Rounding and detachment of 293T cells after overexpression of the full-length cDNA of 4-9. Phase-contrast micrographs are shown of 293T cells transfected with pEFBOS (control plasmid) (A) or the full-length native 4-9/pEFBOS (B). Bar, 50 ixm.
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Our understanding of lympho-hematopoietic microenvironments is incomplete, and a new cloning strategy was developed to identify molecules that bind to B lineage lymphocyte precursors. A cell sorting procedure was used for initial enrichment of cDNAs from stromal cell mRNA that contained signal sequences and were therefore likely to encode transmemb...
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... sequence plus the epitope tag and transmembrane domain of tissue factor). This was also true when the entire extracellular portion was overexpressed with the tissue factor transmembrane domain (data not shown). However, cells expressing the full-length sequence assumed a rounded morphology and detached from the dish within 2 d of transfection (Fig. 7). Since the change occurred before confluence was reached, it did not result from overgrowth of contact-inhibited ...
Citations
... STIM1 is considered a molecule related to the binding of B lymphocytes to stromal cells outside of the Ca 2+ signaling pathway. 30 In AS, STIM1 initiates and develops plaque formation. 31 STIM1 is regulated by miRNAs such as miR-541-3p, miR-185, and miR-641, and participates in the proliferation of VSMCs. ...
Circular RNAs (circRNAs) regulate the function of vascular smooth muscle cells (VSMCs) in atherosclerosis (AS) progression. We aimed to explore the role of circUSP9X in oxidized low-density lipoprotein (ox-LDL)-induced VSMCs. Cell proliferation was assessed using cell counting kit-8 and EDU assays. Cell migration was evaluated using Transwell and wound healing assays. The interaction between circUSP9X or STIM1 and miR-599 was analyzed using dual-luciferase reporter and RNA pull-down assays. Their levels were examined using quantitative real-time PCR. CircUSP9X and STIM1 expression was increased, whereas miR-599 expression was reduced in the serum of patients with AS and ox-LDL-stimulated VSMCs. Overexpression of circUSP9X facilitated the proliferation and migration of VSMCs induced by ox-LDL. CircUSP9X sponged miR-599, which targeted STIM1. MiR-599 reversed the effects induced by circUSP9X, and STIM1 reversed the effects induced by miR-599. Taken together, CircUSP9X promoted proliferation and migration in ox-LDL-treated VSMCs via the miR-599/STIM1 axis, providing a theoretical basis for the role of circUSP9X/miR-599/STIM1 axis in AS.
... Store-operated Ca 2+ channels (SOCCs), also known as calcium release-activated Ca 2+ channels [11], consist of calcium-sensing stromal interaction molecules (STIMs) within the ER membrane and pore-forming Orai proteins in the plasma membrane [12]. STIM1 is a transmembrane protein originally described in immune cells [13] that plays a key role as a main activator of store-operated channels and membrane-associated calcium sensors in the ER [14]. STIM1 also binds directly to the C-terminus of the Ca V 1.2 α1 subunit, suppressing their depolarization-triggered opening ( Figure 1A) and inducing their internalization [15,16]. ...
... When the Ca 2+ content of the ER begins to decline, the protein kinase C (PKC) stimulates the influx of Ca 2+ through the store-operated channels (SOC) (10) and the mitochondria assume the role of the Ca 2+ reservoir, rapidly accumulating large amounts of Ca 2+ and slowly releasing it (11). The overload of Ca 2+ in the mitochondria increases ROS levels and its release to the cytosol (12), where they enhance the [Ca 2+ ] i by stimulating Ca 2+ channels and inhibiting their expulsion mechanisms, damaging lipids, cell proteins, and DNA (13). Increases in ROS and Ca 2+ levels activate calpains and Ca 2+ /calmodulin-dependent protein kinase II (CAMKII). ...
Signals of nerve impulses are transmitted to excitatory cells to induce the action of organs via the activation of Ca2+ entry through voltage-gated Ca2+ channels (VGCC), which are classified based on their activation threshold into high- and low-voltage activated channels, expressed specifically for each organ [...]
... Supporting information-This article contains supporting information (28,(88)(89)(90)(91)(92)(93)(94). ...
Intracellular calcium signaling is essential for many cellular processes, including store-operated Ca2+ entry (SOCE), which is initiated by stromal interaction molecule 1 (STIM1) detecting endoplasmic reticulum (ER) Ca2+ depletion. STIM1 is also activated by temperature independently of ER Ca2+ depletion. Here we provide evidence, from advanced molecular dynamics simulations, that EF-SAM may act as a true temperature sensor for STIM1, with prompt and extended unfolding of the hidden EF-hand subdomain (hEF) even at slightly elevated temperatures, exposing a highly conserved hydrophobic Phe108. Our study also suggests an interplay between Ca2+ and temperature sensing, as both, the canonical EF-hand subdomain (cEF) and the hidden EF-hand subdomain (hEF), exhibit much higher thermal stability in the Ca2+-loaded form compared to the Ca2+-free form. The SAM domain, surprisingly, displays high thermal stability compared to the EF-hands, and may act as a stabilizer for the latter. We propose a modular architecture for the EF-hand-SAM domain of STIM1 composed of a thermal sensor (hEF), a Ca2+ sensor (cEF), and a stabilizing domain (SAM). Our findings provide important insights into the mechanism of temperature-dependent regulation of STIM1, which has broad implications for understanding the role of temperature in cellular physiology.
... One may be puzzled by the nomenclature of proteins in science, but it is quite easily explained: the person(s) who discover the protein get(s) to name it. For STIM1, the name stems from the identification of the first human form as cell adhesion molecule (necessary for attachment) in the stroma, the supporting tissue of an organ [18]. Even though the naming was later found to be inaccurate, it was still retained. ...
All human life starts with a calcium (Ca2+) wave. This ion regulates a plethora of cellular functions ranging from fertilisation and birth to development and cell death. A sophisticated system is responsible for maintaining the essential, tight concentration of calcium within cells. Intricate components of this Ca2+ network are store-operated calcium channels in the cells’ membrane. The best-characterised store-operated channel is the Ca2+ release-activated Ca2+ (CRAC) channel. Currents through CRAC channels are critically dependent on the correct function of two proteins: STIM1 and Orai1. A disruption of the precise mechanism of Ca2+ entry through CRAC channels can lead to defects and in turn to severe impacts on our health. Mutations in either STIM1 or Orai1 proteins can have consequences on our immune cells, the cardiac and nervous system, the hormonal balance, muscle function, and many more. There is solid evidence that altered Ca2+ signalling through CRAC channels is involved in the hallmarks of cancer development: uncontrolled cell growth, resistance to cell death, migration, invasion, and metastasis. In this work we highlight the importance of Ca2+ and its role in human health and disease with focus on CRAC channels.
... In 2005 two independent studies, both using siRNA arrays, identified for the first time, that STIM1 played a central role in mediating SOCE (Liou et al., 2005;Roos et al., 2005). In 1996 there were two reports describing a protein of unknown function, one identified a gene called GOK that was predicted to encode a protein that contained a transmembrane helix (Parker et al., 1996), the other identified a stromal interacting molecule (SIM) (Oritani and Kincade, 1996). SIM and GOK were subsequently named STIM1. ...
Tight spatiotemporal regulation of intracellular Ca2+ plays a critical role in regulating diverse cellular functions including cell survival, metabolism, and transcription. As a result, eukaryotic cells have developed a wide variety of mechanisms for controlling Ca2+ influx and efflux across the plasma membrane as well as Ca2+ release and uptake from intracellular stores. The STIM and Orai protein families comprising of STIM1, STIM2, Orai1, Orai2, and Orai3, are evolutionarily highly conserved proteins that are core components of all mammalian Ca2+ signaling systems. STIM1 and Orai1 are considered key players in the regulation of Store Operated Calcium Entry (SOCE), where release of Ca2+ from intracellular stores such as the Endoplasmic/Sarcoplasmic reticulum (ER/SR) triggers Ca2+ influx across the plasma membrane. SOCE, which has been widely characterized in non-excitable cells, plays a central role in Ca2+-dependent transcriptional regulation. In addition to their role in Ca2+ signaling, STIM1 and Orai1 have been shown to contribute to the regulation of metabolism and mitochondrial function. STIM and Orai proteins are also subject to redox modifications, which influence their activities. Considering their ubiquitous expression, there has been increasing interest in the roles of STIM and Orai proteins in excitable cells such as neurons and myocytes. While controversy remains as to the importance of SOCE in excitable cells, STIM1 and Orai1 are essential for cellular homeostasis and their disruption is linked to various diseases associated with aging such as cardiovascular disease and neurodegeneration. The recent identification of splice variants for most STIM and Orai isoforms while complicating our understanding of their function, may also provide insight into some of the current contradictions on their roles. Therefore, the goal of this review is to describe our current understanding of the molecular regulation of STIM and Orai proteins and their roles in normal physiology and diseases of aging, with a particular focus on heart disease and neurodegeneration.
... Stromal interaction molecule proteins were originally identified as stromal cell surface molecules that interact with blood cell precursors and act as recessive tumor suppressor genes [7,8]. STIM1 is a type I single-pass transmembrane (TMEM) protein in the ER membrane. ...
Store-operated Ca²⁺ entry (SOCE) is a major pathway for calcium signaling, which regulates almost every biological process, involving cell proliferation, differentiation, movement and death. Stromal interaction molecule (STIM) and ORAI calcium release-activated calcium modulator (ORAI) are the two major proteins involved in SOCE. With the deepening of studies, more and more proteins are found to be able to regulate SOCE, among which the transmembrane (TMEM) family proteins are worth paying more attention. In addition, the ORAI proteins belong to the TMEM family themselves. As the name suggests, TMEM family is a type of proteins that spans biological membranes including plasma membrane and membrane of organelles. TMEM proteins are in a large family with more than 300 proteins that have been already identified, while the functional knowledge about the proteins is preliminary. In this review, we mainly summarized the TMEM proteins that are involved in SOCE, to better describe a picture of the interaction between STIM and ORAI proteins during SOCE and its downstream signaling pathways, as well as to provide an idea for the study of the TMEM family proteins.
... This difference is the result of a di-lysine ER retention sequence within the C-terminal domain of STIM2 only [18]. Interestingly, STIM1 was initially identified as a surface protein on pre-B lymphocyte that interacts with stromal cells in bone marrow and contributes to their differentiation into B cells [13,21]. There is little reason to believe that PM-STIM1 contributes to SOCE, as the possibility that translocation to the PM contributes to SOCE is not believed to occur [20,22]. ...
Store-operated calcium entry (SOCE) is mediated by the endoplasmic reticulum (ER) Ca²⁺ sensors stromal interaction molecules (STIM1 and STIM2) and the plasma membrane Orai (Orai1, Orai2, Orai3) Ca²⁺ channels. Although primarily regulated by ER Ca²⁺ content, there have been numerous studies over the last 15 years demonstrating that all 5 proteins are also regulated through post-translational modification (PTM). Focusing primarily on phosphorylation, glycosylation and redox modification, this review focuses on how PTMs modulate the key events in SOCE; Ca²⁺ sensing, STIM translocation, Orai interaction and/or Orai1 activation.
... In order to detail this mechanism, the structural elements present in ORAI and STIM proteins will be detailed thereafter. The STIM gene was cloned in 1996 by two independent teams (Oritani & Kincade, 1996;Parker et al, 1996). If Parker's team cloned the gene and named it GOK, they did not find any function for the newly discovered protein as it was not showing any sequence homology with other known proteins at the time. ...
The store operated calcium (Ca2+) entry (SOCE) represents the entry of Ca2+ through the cell’s plasma membrane consecutive to an endoplasmic reticulum (ER) Ca2+ store depletion. This process is described as one of the main calcium (Ca2+) pathway in the cells. Its importance is highlighted by the severe syndromes induced by loss or gain of function mutation of its constituent named severe combined immunodeficiency (SCID) and tubular aggregate myopathy (TAM)/Stormorken syndrome (STRMK) respectively. SOCE is the result of interaction between two families of proteins, the ER residing protein family Stromal interaction molecule (STIM 1&2) and the plasmalemmal proteins called ORAI (1-3). The classic molecular choreography of SOCE activation is described as follow: a drop in ER-Ca2+ content is detected by the EF-hand domain present in the STIM protein. Following ER Ca2+ depletion, STIM protein oligomerize and translocate to ER- plasma membrane (PM) junctions where they bind and activate ORAI1 composed channel called Ca2+ release activated Ca2+ channel providing SOCE. Interestingly, it appears that this choreography is much more complex than initially thought with the involvement of other STIM and ORAI isoforms (STIM2 and ORAI2,3). The involvement of these isoforms affects the properties of SOCE by modulating its Ca2+ signature resulting in different cellular answers. Especially, it was shown that heteromeric channels composed of ORAI1 and ORAI3 protein are defining an oncogenic switch in prostate cancer cell lines that lead to the more aggressive phenotype. However, the study of the mechanisms leading to the creation of ORAI1/3 channels at the expanse of ORAI1-only channels is problematic due to technical limitations. For example, most of investigations are performed in overexpression or downregulation system where endogenous protein are still present and might blur the results of experiments. The goal of this PhD was to use high end techniques in order to study the mechanisms of ORAI1/3 interactions without facing the limitations mentioned above. Specifically, we implemented and used CRISPR/Cas9 technique to generate double knockout (KO) cell lines for ORAI1 and 3 proteins. We used these “ORAI1/3 free cells” to perform quantitative microscopy experiments. Specifically, we expressed fluorescently tagged ORAI1 and ORAI3 proteins and performed FLIM-FRET (fluorescence lifetime imaging microscopy - Förster resonance energy transfer) experiments enabling us to follow their association process in answer to different stimulations. We thus demonstrated that the association between ORAI1 and ORAI3 is a dynamic process in the cells. Additionally, we took advantage of these KO cell lines to study the role of ORAI1/3 protein and SOCE in HEK-293 and PC3 cells physiology. We thus demonstrated that ORAI1 protein and SOCE only presented a limited role in the maintenance of HEK-293 physiology, while ORAI1 and ORAI3 are important to maintain migrative properties of the cancerous PC3 cells.
... By contrast, stimulation of IP 3 Rs (and RyRs) promotes cell cycle progression of stem cells, pancreatic beta cells, renal cells, and more. STIM, a type I transmembrane protein, was originally identified during a search for transmembrane and secretory proteins in stromal and pre-B lymphocytes [84,87]. The role of STIM in [Ca 2+ ] i signaling was later confirmed by independent work of two groups using high-throughput RNAi screens to identify inhibitors of thapsigargin evoked CRAC current (ICRAC) [88][89][90]. ...
... The coiledcoiled domains experience a shift in their conformation, thus exposing the SOAR/OASF region for interaction with ORAI channels on the plasma membrane [120]. STIM-ORAI functional coupling for SOCE pore formation requires 3 STIM dimers interacting with one ORAI hexamer [87]. STIM dimer composition and function vary under different cellular states. ...
Intracellular Ca2+ distribution is a tightly regulated process. Numerous Ca2+ chelating, storage, and transport mechanisms are required to maintain normal cellular physiology. Ca2+-binding proteins, mainly calmodulin and calbindins, sequester free intracellular Ca2+ ions and apportion or transport them to signaling hubs needing the cations. Ca2+ channels, ATP-driven pumps, and exchangers assist the binding proteins in transferring the ions to and from appropriate cellular compartments. Some, such as the endoplasmic reticulum, mitochondria, and lysosomes, act as Ca2+ repositories. Cellular Ca2+ homeostasis is inefficient without the active contribution of these organelles. Moreover, certain key cellular processes also rely on inter-organellar Ca2+ signaling. This review attempts to encapsulate the structure, function, and regulation of major intracellular Ca2+ buffers, sensors, channels, and signaling molecules before highlighting how cancer cells manipulate them to survive and thrive. The spotlight is then shifted to the slow pace of translating such research findings into anticancer therapeutics. We use the PubMed database to highlight current clinical studies that target intracellular Ca2+ signaling. Drug repurposing and improving the delivery of small molecule therapeutics are further discussed as promising strategies for speeding therapeutic development in this area.
... STIMs, initially named GOKs, are ER Ca 2+ -sensing proteins in the SOCE pathway. STIM1 was initially studied in the mid-1990s and was first described as a transmembrane glycoprotein that is involved in cell-cell interactions in hematopoietic cells and acts as a tumor cell growth suppressor [16,17]. In 2005, it was presented as an essential protein involved in the activation of SOCE [18,19]. ...
Alzheimer’s disease (AD) is the most common neurodegenerative disorder. Although the pathological hallmarks of AD have been identified, the derived therapies cannot effectively slow down or stop disease progression; hence, it is likely that other pathogenic mechanisms are involved in AD pathogenesis. Intracellular calcium (Ca2+) dyshomeostasis has been consistently observed in AD patients and numerous AD models and may emerge prior to the development of amyloid plaques and neurofibrillary tangles. Thus, intracellular Ca2+ disruptions are believed to play an important role in AD development and could serve as promising therapeutic intervention targets.
One of the disrupted intracellular Ca2+ signaling pathways manifested in AD is attenuated storeoperated Ca2+ entry (SOCE). SOCE is an extracellular Ca2+ entry mechanism mainly triggered by intracellular Ca2+ store depletion. Maintaining normal SOCE function not only provides a means for the cell to replenish ER Ca2+ stores but also serves as a cellular signal that maintains normal neuronal functions, including excitability, neurogenesis, neurotransmission, synaptic plasticity, and gene expression. However, normal SOCE function is diminished in AD, resulting in disrupted neuronal spine stability and synaptic plasticity and the promotion of amyloidogenesis. Mounting evidence suggests that rectifying diminished SOCE in neurons may intervene with the progression of AD. In this review, the mechanisms of SOCE disruption and the associated pathogenic impacts on AD will be discussed. We will also highlight the potential therapeutic targets or approaches that may help ameliorate SOCE deficits for AD treatment.
