The extracellular calcium-sensing receptor and cell–cell signaling in epithelia

Hofer, Aldebaran M.; Gerbino, Andrea; Caroppo, Rosa; Curci, Silvana

doi:10.1016/j.ceca.2003.10.021

Cited by 40 publications

(26 citation statements)

References 74 publications

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“…CaR is concentrated in nerve terminals (Ruat et al, 1995) and is often restricted to particular domains of polarized cells (e.g. apical versus basolateral) (Hebert et al, 2004;Hofer et al, 2004;Sands et al, 1997). The same receptor has been identified in a wide variety of organisms, ranging from mammals, amphibians, birds and fish, and there is functional evidence for a CaR-like receptor in Paramecium (Klauke et al, 2000).…”

Section: + Sensors In Animal Cellsmentioning

confidence: 99%

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Another dimension to calcium signaling: a look at extracellular calcium

Hofer

2005

Journal of Cell Science

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Cell biologists know the calcium ion best as a vital intracellular second messenger that governs countless cellular functions. However, the recent identification of cell-surface detectors for extracellular Ca2+ has prompted consideration of whether Ca2+ also functions as a signaling molecule in the extracellular milieu. The cast of Ca2+ sensors includes the well-characterized extracellular-Ca2+-sensing receptor, a G-protein-coupled receptor originally isolated from the parathyroid gland. In addition, other receptors, channels and membrane proteins, such as gap junction hemichannels, metabotropic glutamate receptors, HERG K+ channels and the receptor Notch, are all sensitive to external [Ca2+] fluctuations. A recently cloned Ca2+ sensor (CAS) in Arabidopsis extends this concept to the plant kingdom. Emerging evidence indicates that [Ca2+] in the local microenvironment outside the cell undergoes alterations potentially sufficient to exert biological actions through these sensor proteins. The extracellular space might therefore constitute a much more dynamic Ca2+ signaling compartment than previously appreciated.

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Section: + Sensors In Animal Cellsmentioning

confidence: 99%

“…t-tubules) than these tissueaveraged measurements indicate, or in other restricted Journal of Cell Science 118 (5) (Caroppo et al, 2001;Hofer et al, 2004). When Ins(1,4,5)P 3 production is terminated, reuptake of Ca 2+ into internal stores mediated by the sarco-endoplasmic reticulum ATPase (SERCA) causes Ca 2+ entry to cease.…”

Section: Mechanisms Camentioning

confidence: 99%

Another dimension to calcium signaling: a look at extracellular calcium

Hofer

2005

Journal of Cell Science

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“…After 100 minutes the TEER for the calcium treatment had fallen to a level similar to the glucose control (see Figure 2), indicating decreased cellular activity, which is associated with reduced capacity to form products to facilitate receptors and transporters necessary for the uptake of calcium (Hofer et al, 2004).…”

Section: Resultsmentioning

confidence: 99%

“…Increase in TEER is consequent to transcellular transport of ions into the cell and is caused by constriction of tight junctions (see Figure 1) (Pappenheimer and Volpp, 1992). Additionally, transport of nutrients into the cell results in the formation and activation of receptors, transporters, buffers and stores necessary for maintenance of the cellular environment (Thorens, 1993, Saris et al, 2000, Hofer et al, 2004.…”

Section: Resultsmentioning

confidence: 99%

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The Influence of Dietary Components on Absorption Mechanisms at the Intestinal Monolayer

Durham

Staples

Jones

2006

13th World Congress of Food Science &Amp; Technology

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The influence of nutrients lactose, magnesium and calcium on the absorption mechanisms of the small intestine was investigated. Two in-vitro models of the intestine incorporating Caco-2 cell monolayers were applied to examine the effect of these treatments at concentrations expected in-vivo from milk. Effects were examined by measuring changes in intestinal barrier function and nutrient absorption. Fluctuations in paracellular intestinal barrier were detected by epithelial voltohmeter measuring epithelial electrical resistance. The glucose control peaked at 12 ohms at 1 minute then declined. The calcium treated monolayer peaked in resistance at 40 ohms at 10 minutes declining thereafter. The magnesium treatment increased monolayer resistance by 42 ohms at 1 minute, which was sustained for 100 minutes (±10 ohms). The lactose treated cells had sustained increase in resistance reaching 27 ohms at 100 minutes. Transcellular uptake of calcium, magnesium and phosphorus of the intestinal cells at 100 minutes was determined by ICP-AES. Mineral uptake of calcium treated cells was identical to the glucose control. The magnesium treated cells had significantly higher calcium uptake, (+58%) and lactose treatment, a significantly higher phosphorus uptake, (+12%) compared to the glucose control. These results help elucidate the action of dairy components on the functioning intestinal cell and monolayer. Highlighted is the role of lactose whose ratelimited hydrolysis results in gradual release of saccharides to the intestine, causing minimal impact on permeability in contrast to the glucose control. This work further demonstrates Caco-2 cell models are useful tools that may be used for nutritional investigations leading to the formulation of functional foods.

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Mechanotransduction

Tschumperlin¹

2011

Comprehensive Physiology

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Physical forces are central players in development and morphogenesis, provide an ever-present backdrop influencing physiological functions, and contribute to a variety of pathologies. Mechanotransduction encompasses the rich variety of ways in which cells and tissues convert cues from their physical environment into biochemical signals. These cues include tensile, compressive and shear stresses, and the stiffness or elastic modulus of the tissues in which cells reside. This article focuses on the proximal events that lead directly from a change in physical state to a change in cell-signaling state. A large body of evidence demonstrates a prominent role for the extracellular matrix, the intracellular cytoskeleton, and the cell matrix adhesions that link these networks in transduction of the mechanical environment. Recent work emphasizes the important role of physical unfolding or conformational changes in proteins induced by mechanical loading, with examples identified both within the focal adhesion complex at the cell-matrix interface and in extracellular matrix proteins themselves. Beyond these adhesion and matrix-based mechanisms, classical and new mechanisms of mechanotransduction reside in stretch-activated ion channels, the coupling of physical forces to interstitial autocrine and paracrine signaling, force-induced activation of extracellular proteins, and physical effects directly transmitted to the cell's nucleus. Rapid progress is leading to detailed delineation of molecular mechanisms by which the physical environment shapes cellular signaling events, opening up avenues for exploring how mechanotransduction pathways are integrated into physiological and pathophysiological cellular and tissue processes.

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The extracellular calcium-sensing receptor and cell–cell signaling in epithelia

Cited by 40 publications

References 74 publications

Another dimension to calcium signaling: a look at extracellular calcium

Another dimension to calcium signaling: a look at extracellular calcium

The Influence of Dietary Components on Absorption Mechanisms at the Intestinal Monolayer

Mechanotransduction

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