ZO (protein)

ZO ( lat. Zonula Occludens ) is a protein that occurs exclusively on the cytoplasmic side of the tight junctions . There it interacts u. a. with the proteins occludin and claudin as well as with the actin filaments of the cytoskeleton . It thus connects the tight junctions with the cell skeleton and contributes to stability. So far, three isoforms (ZO-1, ZO-2 and ZO-3) are known.

ZO1 (red) in human endothelial cells

ZO-1 was discovered in 1986 by Bruce R. Stevenson's group at Yale . The researchers used an extract from rat liver enriched with tight junctions to isolate the 200  kDa protein.

ZO-2 was discovered in 1991 by Barry Gumbiner and others at UC San Francisco . The researchers looked for proteins that bind to the previously discovered ZO-1 and found a molecule (M _r 160 kDa) in kidney epithelial cells of dogs ( MDCK cell line).

ZO-3 was discovered in 1993 by Maria Susana Balda's research group in Yale when they were investigating the behavior of tight junctions under low Ca ²⁺ concentrations.

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1. ↑ BR Stevenson, JD Siliciano, MS Mooseker, Goodenough DA: Identification of ZO-I: A high molecular weight polypeptides Associated with the tight junction (zonula occludens) in a Variety of epithelia. In: J Cell Biol . 103 (3), Sep 1986, pp. 755-766. PMID 3528172
2. ↑ B. Gumbiner, T. Lowenkopf, D. Apatira: Identification of a 160-kDa polypeptide that binds to the tight junction protein ZO-1. In: Proc Natl Acad Sci U.S.A. 88 (8), Apr 15, 1991, pp. 3460-3464. PMID 2014265
3. ↑ MS Balda, L. Gonzalez-Mariscal, K. Matter, M. Cereijido, JM Anderson: Assembly of the tight junction: the role of diacylglycerol. In: J Cell Biol. 123 (2), Oct 1993, pp. 293-302. PMID 8408213