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Nat Cell Biol. 2004 Dec;6(12):1173-9. Epub 2004 Nov 21.

A novel actin barbed-end-capping activity in EPS-8 regulates apical morphogenesis in intestinal cells of Caenorhabditis elegans.

Author information

1
IFOM Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy.

Abstract

Redundant gene function frequently hampers investigations of the physiological roles of mammalian proteins. This is the case for Eps8, a receptor tyrosine kinase (RTK) substrate that participates in the activation of the Rac-specific guanine nucleotide-exchange function of Sos1 (refs 2-5), thereby regulating actin remodelling by RTKs. EPS8-knockout mice, however, exhibit no evident phenotype, owing to the redundant function of three other EPS8-related genes. Here we show that in the nematode Caenorhabditis elegans, only one orthologue of the EPS8 gene exists, which gives rise to two alternatively spliced isoforms, EPS-8A and EPS-8B, differing at their carboxyl termini. In the nematode, eps-8 is essential for embryonic development. Furthermore, EPS-8A, but not EPS-8B, is specifically required for proper apical morphogenesis in the intestinal cells. This latter phenotype could be precisely correlated with a previously unknown actin barbed-end-capping activity, which is present in the C terminus of the EPS-8A isoform. Therefore, nematode genetics allowed not only the unmasking of distinct EPS-8-linked phenotypes, but also the definition of a novel function for this molecule in actin dynamics.

PMID:
15558032
DOI:
10.1038/ncb1198
[Indexed for MEDLINE]

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