The specialization of septate junctions in regions of tricellular junctions

Graf, F.; Noirot-Timothée, C.; Noirot, Ch.

doi:10.1016/s0022-5320(82)80019-1

Cited by 35 publications

(30 citation statements)

References 7 publications

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“…Such a fixed point could be a tricellular junction, which also allows force generation during cytokinesis (Bosveld et al, 2016). Classical freeze fracture studies (Fristrom, 1982;Graf et al, 1982;Noirot-Timothé e et al, 1982;Staehelin, 1973) as well as our FRAP data suggest that bicellular occluding junctions are connected to tricellular junctions. This connection might be mediated by the tricellular junction proteins Bark beetle (Anakonda) and Gliotactin, which can also interact with bicellular septate junction proteins (Byri et al, 2015;Hildebrandt et al, 2015;Jaspers et al, 2012;Schulte et al, 2003).…”

Section: Discussionmentioning

confidence: 53%

“…A good position for such anchoring would be at the cell vertices. Freeze fracture experiments suggested that bicellular septate junctions are connected to TCJs (Fristrom, 1982;Graf et al, 1982;Noirot-Timothé e et al, 1982) (Figure 1I). FRAP experiments also suggest that newly formed septate junction strands are connected to TCJs ( Figure S4).…”

Section: Septate Junction Development and Dynamics In Drosophila Gliamentioning

confidence: 99%

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The Drosophila Blood-Brain Barrier Adapts to Cell Growth by Unfolding of Pre-existing Septate Junctions

2018

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Graphical Abstract Highlights d Septate junction (SJ) proteins are stable for days d SJ strands are prefigured during embryogenesis and are unfolded during larval stages d The G-protein coupled receptor Moody suppresses interdigitating cell-cell protrusions d Moody promotes formation of continuous SJ strands SUMMARYThe blood-brain barrier is crucial for nervous system function. It is established early during development and stays intact during growth of the brain. In invertebrates, septate junctions are the occluding junctions of this barrier. Here, we used Drosophila to address how septate junctions grow during larval stages when brain size increases dramatically. We show that septate junctions are preassembled as long, highly folded strands during embryonic stages, connecting cell vertices. During subsequent cell growth, these corrugated strands are stretched out and stay intact during larval life with very little protein turnover. The G-protein coupled receptor Moody orchestrates the continuous organization of junctional strands in a process requiring F-actin. Consequently, in moody mutants, septate junction strands cannot properly stretch out during cell growth. To compensate for the loss of blood-brain barrier function, moody mutants form interdigitating cell-cell protrusions, resembling the evolutionary ancient barrier type found in primitive vertebrates or invertebrates such as cuttlefish.

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Section: Discussionmentioning

confidence: 53%

Section: Septate Junction Development and Dynamics In Drosophila Gliamentioning

confidence: 99%

The Drosophila Blood-Brain Barrier Adapts to Cell Growth by Unfolding of Pre-existing Septate Junctions

2018

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“…SJs in insects are categorized into two types: pleated SJs in ectoderm-derived epithelial cells and smooth SJs in endoderm-derived epithelial cells 35 . Electron microscopic observations have shown that specialized structures, namely tricellular junctions, are formed at TCs attached to both types of SJs 36 - 38 . There are long channels with diaphragms at their TCs along the depth of epithelial cells and they are proposed to work as anchors for SJ strands.…”

Section: Tricellular Junctions In Invertebratesmentioning

confidence: 99%

Molecular organization of tricellular tight junctions

et al. 2014

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When the apicolateral border of epithelial cells is compared with a polygon, its sides correspond to the apical junctional complex, where cell adhesion molecules assemble from the plasma membranes of two adjacent cells. On the other hand, its vertices correspond to tricellular contacts, where the corners of three cells meet. Vertebrate tricellular contacts have specialized structures of tight junctions, termed tricellular tight junctions (tTJs). tTJs were identified by electron microscopic observations more than 40 years ago, but have been largely forgotten in epithelial cell biology since then. The identification of tricellulin and angulin family proteins as tTJ-associated membrane proteins has enabled us to study tTJs in terms of not only the paracellular barrier function but also unknown characteristics of epithelial cell corners via molecular biological approaches.

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“…Septierte Verbindungen, die avertebraten-spezifisch sind, stellen einen zwischen epithelialen Zellen von Arthropoden haufig ausgebildeten syrnrnetrischen Kontakttyp dar. Obwohl die Morphologie iiberaus typisch ist und verschiedene Varianten beschrieben sind (Staehelin, 1974;Graf et al, 1982;Noirot-Timothee et al, 1992), ist ihre Funktion nach wie vor nicht bekannt. 'Tight junction'-ahnliche Aufgaben irn Sinne einer parazellularen Diffusionsbarriere werden neben adhasiven Aufgaben diskutiert.…”

Section: Diskussionunclassified

Das Spermathekalepithel der Bienenkönigin (Apis mellifera): Morphologie, alters‐abhängige Veränderungen und Zellkontakte

Kressin

Sommer

Schnorr

1996

Anat Histol Embryol

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The spermatheca of the honey bee queen is covered by a single-layered, uniform, polarised epithelium. The apical cell surface is greatly enlarged by protrusions and plasma membrane infoldings, the basal cell surface by numerous interdigitating, long, small processes. Cytoplasmic organelles are chiefly represented by mitochondria. Numerous microtubuli extend throughout the cytoplasm. Golgi and endoplasmic profiles are rare. The cells are subject to senile degeneration: with increasing age, a variety of cytoplasmic inclusions appear, among which are myelinated membranes, dense bodies and dense filamentous aggregates. The spermathecal epithelium does not seem to be involved in exocrine secretion related to nutrition of the long-term stored spermatozoa. The ultra-structure points, however, to ion transport functions and to an engagement in the maintenance of an adequate physicochemical environment ensuring the viability of the spermatozoa. Cellular junctions are represented by luminal zonulae adherentes, focal cell-cell adhering junctions and hemiadhering junctions along the basal plasmalemma. Desmosomal contacts and cytoskeletal intermediate filaments are missing. Along the lateral plasmalemma, gap junctions and septate junctions are found.

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The specialization of septate junctions in regions of tricellular junctions

Cited by 35 publications

References 7 publications

The Drosophila Blood-Brain Barrier Adapts to Cell Growth by Unfolding of Pre-existing Septate Junctions

The Drosophila Blood-Brain Barrier Adapts to Cell Growth by Unfolding of Pre-existing Septate Junctions

Molecular organization of tricellular tight junctions

Das Spermathekalepithel der Bienenkönigin (Apis mellifera): Morphologie, alters‐abhängige Veränderungen und Zellkontakte

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