Permeability of Membrane Junctions*

Loewenstein, Werner R.

doi:10.1111/j.1749-6632.1966.tb50175.x

Cited by 618 publications

(225 citation statements)

References 60 publications

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“…Both in developing and in mature tissues such exchanges may be of considerable importance for the coordination and regulation of cellular activities (3,5). An estimate of the size of molecules that can be passed through gap-junction channels from one cell to another has been obtained by following the spread or nonspread of injected dye molecules of known molecular weight between adjacent, electrically coupled cells.…”

Section: Discussionmentioning

confidence: 99%

“…One type of cell-to-cell communication appears to be mediated by gap junctions or nexuses (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), specialized intercellular junctions that provide a route for the direct passage of small molecules from cytoplasm to cytoplasm with little loss (8,11,13). Although these junctions can be visualized in standard thin sections (14), in thin sections containing special tracers (4), and by negative staining (15), they can be most readily studied by the freeze-cleaving technique (9,12,16,17).…”

mentioning

confidence: 99%

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Three Types of Gap Junctions Interconnecting Intestinal Epithelial Cells Visualized by Freeze-Etching

1972

Proc. Natl. Acad. Sci. U.S.A.

108

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Gap junctions are specialized membrane regions that seem to mediate intercellular communication. They appear to contain closely packed arrays of equally sized particles all of which, upon freeze-cleaving, remain attached to one membrane leaflet and not to the other. One gap junction cleavage face, therefore, always exhibits a closely packed array of particles, while the other features a corresponding array of pits. By using these morphological criteria, we have been able to distinguish three different types of gap junctions interlinking adjacent epithelial cells of the small intestine. All three types may be found in close proximity to each other, and in all cases, the particles remain attached to the cleavage face of the cytoplasmic membrane leaflet (A-face). The most frequently encountered type-I gap junctions, which have already been observed in many other tissues, possess 8- to 9-nm (80- to 90-Å) particles with a center-to-center spacing of 9-10 nm (90-100 Å) when packed in a hexagonal lattice. Type-II gap junctions are always found in close association with type-I junctions. They can be distinguished from the type-I junctions by the greater size [10-11 nm (100-110 Å) in diameter] and the greater spacing (190-200 Å) of their hexagonally arrayed particles. In contrast, the particles of the type-III gap junctions are arranged in very small rectilinear arrays with a spacing of only 6-8 nm (60-80 Å). Gap junctions may be involved in the control of intercellular flow of different types of regulatory molecules.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Three Types of Gap Junctions Interconnecting Intestinal Epithelial Cells Visualized by Freeze-Etching

1972

Proc. Natl. Acad. Sci. U.S.A.

108

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“…Since many human lung cancers express a variable degree of squamous differentiation (reviewed above), studies have been performed to determine the mechanism which allows transformed cells to proliferate and reversibly express a squamous (i.e, non-terminal) phenotype. Formaldehyde is a widely distributed occupational and environmental toxin (6,13,14) and poses a genotoxic and carcinogenic risk to humans (55, 120,176). Early studies by Florey et a1 (39) demonstrated that intratracheally instilled formaldehyde (-40-80 mM) induced epidermoid metaplasia and increased the mitotic activity.…”

Section: Cohimunicationmentioning

confidence: 99%

Intercellular Communication in Bronchial Epithelial Cells: Review of Evidence for a Possible Role in Lung Carcinogenesis

et al. 1990

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A challenging aspect of lung carcinogenesis is the elucidation of the mechanisms which permit initiated bronchial epithelial cells to attain a growth advantage over normal bronchial epithelial cells, and subsequently evolve into a malignant phenotype. In this review, the effects of interactions between normal and transformed cells, and the potential role of representative extrinsic factors on cell-cell communication are discussed. Evidence is presented to show how cell injury and the effects of serum and calcium may affect morphology and communication, and tumor development. A large number of autocrine-paracnne factors (e.g., TGFp, TGFa) are released by bronchial epithelial cells. These factors may inhibit or promote the proliferation of normal and transformed bronchial epithelial cells, respectively. The ability of certain injurious and tumor promoting agents (e.g., formaldehyde, TPA) to select for the transformed phenotype may involve selective cell injury, the induction of terminal differentiation and an inhibition of gap junction communication among normal BE cells.

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“…The structure of gap junctions has become of interest in view of physiological studies suggesting that they mediate intercellular communication (5,9,10; for a recent review, see reference 1) . Several structural models have been proposed which combine physiological, electron microscope, and x-ray diffraction data (9,12,13,16) .…”

mentioning

confidence: 99%

“…Several structural models have been proposed which combine physiological, electron microscope, and x-ray diffraction data (9,12,13,16) . In these models, the junction is composed of two closely apposed plasma membranes, separated by a narrow extracellular gap (18) .…”

mentioning

confidence: 99%

On gap junction structure.

Zampighi¹,

Corless²,

Robertson³

1980

The Journal of Cell Biology

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We have studied the stain distribution within rat liver gap junctions for specimens prepared by thin sectioning and negative staining . Pools of stain molecules exist in two specific locations with respect to the distinctive morphological units (connexons) of the junction . One pool of stain surrounds the connexons and is restricted to the extracellular space in the gap between the adjacent plasma membranes. The other pool of stain is located along the central axis of each connexon, measures 1-2 nm in diameter and 4-5 nm in length, and is restricted to the gap region . On rare occasions, barely discernible linear densities seem to extend from this latter pool of stain and traverse the entire width of the junction . The data indicate the existence of a hydrophilic cavity along the central axis of the connexon which, in most instances, is restricted to the gap region . However, the precise depth to which this cavity may further extend along the connexon axis is still uncertain .

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Permeability of Membrane Junctions*

Cited by 618 publications

References 60 publications

Three Types of Gap Junctions Interconnecting Intestinal Epithelial Cells Visualized by Freeze-Etching

Three Types of Gap Junctions Interconnecting Intestinal Epithelial Cells Visualized by Freeze-Etching

Intercellular Communication in Bronchial Epithelial Cells: Review of Evidence for a Possible Role in Lung Carcinogenesis

On gap junction structure.

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