Gap junction structures. I. Correlated electron microscopy and x-ray diffraction.

Caspar, D. L. D.; Goodenough, D A; Makowski, Lee; Phillips, W.C.

doi:10.1083/jcb.74.2.605

Cited by 326 publications

(140 citation statements)

References 19 publications

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“…However, the arrangement of the major subunit (subunit c) of the membrane sector, V o , is known. This is as a result of the unexpected finding that subunit c is the sole protein component of another membrane complex found in metazoans, the connexon channel of gap junction structures [7], which was first imaged 20 years ago [8,9].…”

Section: Overviewmentioning

confidence: 99%

“…Both Vma5p and Vma13p may be peripheral to the core V 1 complex. Cross-linking studies on the coated vesicle enzyme indicate that Vma4p (4), Vma5p (5) and Vma8p (8) are in contact with the 16 kDa proteolipid of V o (3). V o (subunits shown in light pink) comprises a core formed from a hexameric complex of the 16 kDa proteolipid Vma3p (3) which contains, at least in part, the pathway of proton translocation.…”

Section: Figure 1 Structural Model Of the Saccharomyces V-atpasementioning

confidence: 99%

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The vacuolar H+-ATPase: a universal proton pump of eukaryotes

Finbow

Harrison

1997

Biochemical Journal

241

179

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The vacuolar H + -ATPase (V-ATPase) is a universal component of eukaryotic organisms. It is present in the membranes of many organelles, where its proton-pumping action creates the low intravacuolar pH found, for example, in lysosomes. In addition, there are a number of differentiated cell types that have V-ATPases on their surface that contribute to the physiological functions of these cells. The V-ATPase is a multi-subunit enzyme composed of a membrane sector and a cytosolic catalytic sector. It is related to the familiar F o F " ATP synthase (F-ATPase), having the same basic architectural construction, and many of the subunits from

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Section: Overviewmentioning

confidence: 99%

Section: Figure 1 Structural Model Of the Saccharomyces V-atpasementioning

confidence: 99%

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

Finbow

Harrison

1997

Biochemical Journal

241

179

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“…8 is tilted almost horizontally and viewed along major axes (large arrows). This long-range order is at first not apparent because of the short-range disorder among the particles (6). The short-range disorder among the particles may be the result of plastic deformation of the particles.…”

Section: Figurementioning

confidence: 99%

The fine structure of a rectifying electrotonic synapse.

Hanna¹,

Keeter²,

Pappas³

1978

The Journal of Cell Biology

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The synapses between the lateral giant axon and the giant motor axon found in the abdominal ganglia of the ventral nerve cord of the crayfish Procambarus clarkii are electronic. The junctional membrane rectifies, favoring impulse transmission from lateral giant fiber to giant motor fiber. This rectifying electronic junction consists of closely apposed membranes indistinguishable from ordinary arthropod gap junctions. The apposed membranes contain intramembrane particles that are -12.5 nm in width. These particles have a central depression and are arranged in a loosely ordered array with a center-to-center spacing of about 20 nm.The only obvious morphological evidence of asymmetry is the presence of vesicles (about 80 nm in diameter) in the cytoplasm adjacent to the junctional region of the presynaptic lateral giant fiber. Vesicles are not present in the adjacent cytoplasm of the postsynaptic giant motor fiber; however, mitochondria and smooth tubular endoplasmic reticulum are more frequent in the cytoplasm of the giant motor fiber.KEY WORDS cell-to-cell communication rectifying electrotonic junction gap junction freeze-fracture -electron microscopy Although most electrotonic junctions behave as fixed resistances connecting coupled cells, a few instances are known in which the junctions rectify. Furshpan and Potter (9) established that transmission at the giant motor synapse of the crayfish is electrical with rectification. Conduction is essentially a one-way transmission from lateral giant fiber to giant motor fiber. When the potential in the lateral giant axon (presynaptic) is positive relative to the potential in the giant motor fiber t Dr. Keeter died 17 February 1976.(postsynaptic), junctional resistance is low. At rest, and when the motor fiber is more positive, junctional resistance is high. Thus orthodromic transmission is favored over antidromic.Robertson (28) and Stifling (30) have suggested that the junctional membranes in this synapse form intimate contact. Our preliminary findings (12,15) indicate that these rectifying junctions may be similar morphologically to the more common linear electrotonic synapses. To positively identify topologically the location of these junctions, nerve cords were initially prepared for scanning electron microscopy. Further studies of this synapse on both sectioned and freeze-fracture preparations were carried out. We were unable to distinguish any structural differences between the 764 J. CELL BIOLOGY 9 The Rockefeller University Press

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“…These hemichannels can then 'dock' with a hemichannel on an adjacent cell to connect the cytoplasms of the respective cells, forming a gap junction. Thousands of these channels come together to form large clusters or plaques that are visible by electron microscopy (Caspar et al, 1977). Gap junctions can have differing permeabilities to molecules and ions depending on their specific connexin composition.…”

Section: The Importance Of Gap Junctionsmentioning

confidence: 99%

Defective channels lead to an impaired skin barrier

Blaydon¹,

Kelsell²

2014

Journal of Cell Science

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Channels are integral membrane proteins that form a pore, allowing the passive movement of ions or molecules across a membrane (along a gradient), either between compartments within a cell, between intracellular and extracellular environments or between adjacent cells. The ability of cells to communicate with one another and with their environment is a crucial part of the normal physiology of a tissue that allows it to carry out its function. Cell communication is particularly important during keratinocyte differentiation and formation of the skin barrier. Keratinocytes in the skin epidermis undergo a programme of apoptosis-driven terminal differentiation, whereby proliferating keratinocytes in the basal (deepest) layer of the epidermis stop proliferating, exit the basal layer and move up through the spinous and granular layers of the epidermis to form the stratum corneum, the external barrier. Genes encoding different families of channel proteins have been found to harbour mutations linked to a variety of rare inherited monogenic skin diseases. In this Commentary, we discuss how human genetic findings in aquaporin (AQP) and transient receptor potential (TRP) channels reveal different mechanisms by which these channel proteins function to ensure the proper formation and maintenance of the skin barrier.

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Gap junction structures. I. Correlated electron microscopy and x-ray diffraction.

Cited by 326 publications

References 19 publications

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

The fine structure of a rectifying electrotonic synapse.

Defective channels lead to an impaired skin barrier

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