Molecular Basis for Cation Selectivity in Claudin-2–based Paracellular Pores: Identification of an Electrostatic Interaction Site

Yu, Alan; Cheng, Mary Hongying; Angelow, Susanne; Günzel, Dorothee; Kanzawa, Sanae A.; Schneeberger, Eveline E.; Fromm, Michael; Coalson, Rob D.

doi:10.1083/jcb1841oia3

Cited by 80 publications

(174 citation statements)

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“…It was therefore no surprise that with our conductance scanning technique (Gitter et al, 1997;Yu et al, 2009) we did not detect elevated local conductances at tTJs (data not shown). This aspect is in accordance with results published by Cereijido et al (1982) for the Necturus gallbladder.…”

Section: In Btjs Tricellulin Reduces Strand Discontinuities and By Thmentioning

confidence: 96%

“…It is unclear yet, whether strand linearity is a direct determinant of permeability or if it represents an epiphenomenon of an altered composition of proteins within the TJ. Although homophilic interaction of single claudins has started to be understood (Yu et al, 2009;Piontek et al, 2008), the molecular base of strand formation of an ensemble of TJ proteins has not been experimentally addressed.…”

Section: In Btjs Tricellulin Reduces Strand Discontinuities and By Thmentioning

confidence: 99%

“…The second estimation for a lower limit of conductance used data for the claudin-2 pore, as a highly selective and narrow pore. This pore has been modeled to be 3.2 nm in length and 0.75 nm in diameter, and its conductance was estimated to be 70 -100 pS by calculations depending on Brownian Dynamics simulations (Yu et al, 2009). Assuming that the tricellular central tube (Staehelin, 1973) behaved as if it was constructed from units with the dimensions and characteristics of claudin-2 pores, we calculated the equivalent number of claudin-2 pore units to be 178 in parallel, ϫ 313 in series.…”

Section: In Btjs Tricellulin Reduces Strand Discontinuities and By Thmentioning

confidence: 99%

“…Single-ion permeabilities were determined from dilution or bi-ionic potentials and the Goldman-Hodgkin-Katz equation as reported previously (Amasheh et al, 2002;Gü nzel et al, 2009;Yu et al;. Briefly, NaCl dilution potentials were measured by switching one hemichamber to a solution containing a reduced concentration of NaCl and all other components identical to standard Ringer's.…”

Section: Electrophysiologymentioning

confidence: 99%

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Tricellulin Forms a Barrier to Macromolecules in Tricellular Tight Junctions without Affecting Ion Permeability

Krug

Amasheh

Richter

et al. 2009

MBoC

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Tricellulin is a tight junction protein localized in tricellular tight junctions (tTJs), the meeting points of three cells, but also in bicellular tight junctions (bTJs). To investigate its specific barrier functions in bTJs and tTJs, TRIC-a was expressed in low-level tricellulin-expressing cells, and MDCK II, either in all TJs or only in tTJs. When expressed in all TJs, tricellulin increased paracellular electrical resistance and decreased permeability to ions and larger solutes, which are associated with enhanced ultrastructural integrity of bTJs toward enhanced strand linearity. In tTJs in contrast, ultrastructure was unchanged and tricellulin minimized permeability to macromolecules but not to ions. This paradox is explained by properties of the tTJ central tube which is wide enough for passage of macromolecules, but too rare to contribute significantly to ion permeability. In conclusion, at low tricellulin expression the tTJ central tube forms a pathway for macromolecules. At higher expression, tricellulin forms a barrier in tTJs effective only for macromolecules and in bTJs for solutes of all sizes.

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Section: In Btjs Tricellulin Reduces Strand Discontinuities and By Thmentioning

confidence: 96%

Section: In Btjs Tricellulin Reduces Strand Discontinuities and By Thmentioning

confidence: 99%

Section: In Btjs Tricellulin Reduces Strand Discontinuities and By Thmentioning

confidence: 99%

Section: Electrophysiologymentioning

confidence: 99%

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Tricellulin Forms a Barrier to Macromolecules in Tricellular Tight Junctions without Affecting Ion Permeability

Krug

Amasheh

Richter

et al. 2009

MBoC

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“…2C). These pores have a diameter of ~4-8Å depending tissue and molecule analysed [73][74][75] . A second diffusion pathway allows the diffusion of larger solutes, macromolecules up to a size limit of ~30-60Å 72,75 .…”

Section: Regulation Of Paracellular Permeabilitymentioning

confidence: 99%

Tight junctions: from simple barriers to multifunctional molecular gates

Zihni

Mills

Matter

et al. 2016

Nat Rev Mol Cell Biol

1,031

925

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Main body of text: 5983 words 2Epithelia and endothelia separate different tissue compartments and protect multicellular organisms form the outside world. This requires the formation of tight junctions, selective gates that control paracellular diffusion of ions and solutes. Tight junctions also form the border between the apical and basolateral plasma membrane domains and are linked to the machinery that controls apicobasal polarization. Additionally, signalling networks that guide diverse cell behaviours and functions are connected to tight junctions, transmitting information to and from the cytoskeleton, nucleus and different cell adhesion complexes. Here, we discuss recent advances in our understanding of the molecular architecture and cellular functions of tight junctions.Microscopists in the 19 th century described the paracellular space between neighbouring cells within an epithelial sheet to be sealed by a "terminal bar", a structure later resolved by electron microscopy into a composite of distinct cell-cell junctions that is now called the epithelial junctional complex and is formed by tight junctions, adherens junctions and desmosomes 1,2 . As the former two junctions are more tightly associated and often reside at the apical end of the lateral membrane, they are often referred to as the apical junctional complex (however, in endothelia, tight junctions and adherens junctions can be intercalated) (Fig. 1). Tight junctions are essential for barrier formation, and their primary physiological role is to function as paracellular gates that restrict diffusion on the basis of size and charge. Selective paracellular diffusion is an essential process for the maintenance of homoeostasis in organs and tissues. Tight junctions have long been the most enigmatic of all adhesion complexes and eluded a detailed molecular and functional analysis due to their complex architecture. Recent years have witnessed the identification of a large array of components associated with tight junctions implicating these junctions in an unexpected range of different functions, thereby challenging the traditional model, in which tight junctions are considered a simple diffusion barrier formed by a rigid molecular complex. In line with these various functions, mutations in genes encoding tight junction proteins have been linked to a range of inherited human diseases. Additionally, tight junction components are known to be targeted by a number of pathogenic bacteria and viruses, which hijack tight junction proteins to enter and infect cells, or target junctional signalling mechanisms to cross tissue barriers. Although tight junctions are a vertebrate junction, many of their components and functions are evolutionarily conserved (Box 1).The main purpose of this review is to examine the recent advances in the unravelling of the molecular architecture of tight junctions and understanding their functions. We will discuss recent exciting insights into how tight junctions function as signalling platforms that guide cell behaviour and differen...

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Electrophysiologic Analysis of Tight Junction Size and Charge Selectivity

et al. 2021

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Tight junctions form selectively permeable barriers that limit paracellular flux across epithelial‐lined surfaces. Rather than being absolute barriers, tight junctions in many tissues allow ions, water, and other small molecules to cross on the basis of size and charge selectivity via the high‐capacity pore pathway. Most probes currently used to assess tight junction permeability exceed the maximum size capacity of the pore pathway. As a result, available analytical tools have generally been limited to measurement of transepithelial electrical resistances. These provide no information regarding size selectivity and, therefore, cannot be used to distinguish between the pore pathway and the leak pathway, a low‐capacity route that accommodates larger macromolecules. This article describes use of dilution potential and bi‐ionic potential measurements for analysis of tight junction size and charge selectivity within monolayers of cultured epithelial cells. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Culture of MDCK monolayers on semipermeable supports and induction of claudin‐2 expression Basic Protocol 2: Configuring voltage/current clamp and other equipment Basic Protocol 3: Measuring dilution and bi‐ionic potentials Basic Protocol 4: Calculating ion permeabilities and pore diameter Support Protocol: Preparation of agar bridges and electrophysiology rig setup

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Molecular Basis for Cation Selectivity in Claudin-2–based Paracellular Pores: Identification of an Electrostatic Interaction Site

Cited by 80 publications

References 1 publication

Tricellulin Forms a Barrier to Macromolecules in Tricellular Tight Junctions without Affecting Ion Permeability

Tricellulin Forms a Barrier to Macromolecules in Tricellular Tight Junctions without Affecting Ion Permeability

Tight junctions: from simple barriers to multifunctional molecular gates

Electrophysiologic Analysis of Tight Junction Size and Charge Selectivity

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