The Ca2+-activated Cl− channel Ano1 controls microvilli length and membrane surface area in the oocyte

Courjaret, Raphael Jean; Hodeify, Rawad; Hubrack, Satanay; Ibrahim, Awab; Dib, Maya; Da’as, Sahar; Machaca, Khaled

doi:10.1242/jcs.188367

Cited by 17 publications

(15 citation statements)

References 60 publications

(69 reference statements)

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“…In Xenopus oocytes, the Ca 2 + -activated chloride channel Ano1 contributes to this increase in oocyte surface area. Independent of its channel activity, Ano1 regulates microvilli length and scaffolding, leading to stabilization of larger membrane structures (Courjaret et al, 2016). Identifying other cellular systems where the lengths and/or numbers of these various MT-and actin-based linear structures change over development will provide new insights into scaling of these unique organelles.…”

Section: Flagella Cilia Stereocilia and Microvillimentioning

confidence: 99%

Organelle size scaling over embryonic development

Wesley

Mishra

Levy

2020

WIREs Developmental Biology

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Section: Flagella Cilia Stereocilia and Microvillimentioning

confidence: 99%

Organelle size scaling over embryonic development

Wesley

Mishra

Levy

2020

WIREs Developmental Biology

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“…To our knowledge, only the intestine of Vitamin D Receptor KO mice 39 and oocytes of mice deficient for the Ca 2+ -activated Cl − channel Ano 40 show such defects. In both cases, these defects are not fully understood at the molecular level but may indirectly be mediated by some ERM protein expression changes 39,40 .…”

Section: Discussionmentioning

confidence: 99%

The actin nucleator Cobl organises the terminal web of enterocytes

Beer¹,

Delgado²,

Steiniger³

et al. 2020

Sci Rep

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Brush borders of intestinal epithelial cells are mandatory for nutrient uptake. Yet, which actin nucleators are crucial for forming the F-actin bundles supporting microvilli and the actin filaments of the terminal web, in which microvilli are rooted, is unknown. We show that mice lacking the actin nucleator cobl surprisingly did not display reduced microvilli densities or changes in microvillar f-actin bundles or microvilli diameter but particularly in the duodenum displayed increased microvillar length. Interestingly, Cobl-deficient mice furthermore showed a significant widening of the terminal web. Quantitative analyses of high-resolution cryo-scanning electron microscopy (eM) of deep-etched duodenum samples revealed that Cobl is specifically important for the formation of fine filaments in the central terminal web that connect the apical structure of the terminal web underlying the plasma membrane, the microvilli rootlets and the basal structure of the terminal web with each other. Thus, the actin nucleator cobl is critically involved in generating one of the cellular structures of the brush borderdecorated apical cortex of enterocytes representing the absorptive intestinal surface. Surface extensions of epithelial cells (enterocytes) by microvilli are mandatory for nutrient uptake in the gut. New-borns with reduced length of microvilli, as it e.g. occurs in the inherited microvillar inclusion disease, thus usually die during their early infancy 1,2. Yet, despite this importance, it is still unknown which actin nucleators are crucial for forming the F-actin bundles supporting microvilli and the actin filaments of the terminal web, in which microvilli are rooted 3-5. Microvilli are uniform membrane protrusions that are structurally supported by a dense bundle of unbranched actin filaments, that are organised in a very dense, almost hexagonal packing by actin-crosslinking proteins and that show very uniform length in brush borders. This length differs along the intestinal tract with about 1300-1400 nm in the small intestine and only 800 nm in the colon 6. The minus ends of microvillar F-actin bundles reach into the cells as rootlets and are anchored-presumably by plastin 1 (fimbrin) interlinking them with the keratin network 7-in the terminal web, which spans the entire apical cortex of enterocytes 8,9. Although a variety of F-actin-binding proteins including e.g. myosins, tropomyosin, villin, spectrin, ezrin and espin have been identified in biochemical isolations of microvilli and attached terminal web structures 3 , loss-of-function data identifying the actin nucleator(s) that give rise to the F-actin structures in microvilli and/or in the terminal web is lacking. Despite significant scientific efforts during several decades, also microvilli formation and length control in intestinal brush borders still are poorly understood, as i) intestine tissues are not well accessible for molecular manipulations, ii) enterocytes in the murine gut only have a lifespan of a few days and iii) once intestinal microvilli are ...

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“…CaCC are encoded by TMEM16A also known as Anoctamin 1 or Ano1 (Schroeder et al, 2008 ; Yang et al, 2008 ). In Xenopus oocytes, CaCC interact with ERM proteins to regulate the length of microvilli and the membrane surface area (Courjaret et al, 2016 ; Table 1 ). CaCC are activated in response to the sperm-induced Ca 2+ release at fertilization.…”

Section: Xenopus Vs Mammalian Oocytes: Comparison Of Ion Chmentioning

confidence: 99%

Ion Channel Function During Oocyte Maturation and Fertilization

Carvacho

Piesche

Maier

et al. 2018

Front. Cell Dev. Biol.

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The proper maturation of both male and female gametes is essential for supporting fertilization and the early embryonic divisions. In the ovary, immature fully-grown oocytes that are arrested in prophase I of meiosis I are not able to support fertilization. Acquiring fertilization competence requires resumption of meiosis which encompasses the remodeling of multiple signaling pathways and the reorganization of cellular organelles. Collectively, this differentiation endows the egg with the ability to activate at fertilization and to promote the egg-to-embryo transition. Oocyte maturation is associated with changes in the electrical properties of the plasma membrane and alterations in the function and distribution of ion channels. Therefore, variations on the pattern of expression, distribution, and function of ion channels and transporters during oocyte maturation are fundamental to reproductive success. Ion channels and transporters are important in regulating membrane potential, but also in the case of calcium (Ca2+), they play a critical role in modulating intracellular signaling pathways. In the context of fertilization, Ca2+ has been shown to be the universal activator of development at fertilization, playing a central role in early events associated with egg activation and the egg-to-embryo transition. These early events include the block of polyspermy, the completion of meiosis and the transition to the embryonic mitotic divisions. In this review, we discuss the role of ion channels during oocyte maturation, fertilization and early embryonic development. We will describe how ion channel studies in Xenopus oocytes, an extensively studied model of oocyte maturation, translate into a greater understanding of the role of ion channels in mammalian oocyte physiology.

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The Ca2+-activated Cl− channel Ano1 controls microvilli length and membrane surface area in the oocyte

Cited by 17 publications

References 60 publications

Organelle size scaling over embryonic development

Organelle size scaling over embryonic development

The actin nucleator Cobl organises the terminal web of enterocytes

Ion Channel Function During Oocyte Maturation and Fertilization

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