Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article Full Text (PDF, 191K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                            What's this?

© The Rockefeller University Press, 0021-9525/2002/3/941 $5.00
The Journal of Cell Biology, Volume 156, Number 6, March 18, 2002 941-941

Crumbs turns the corner

Growth of the photoreceptor stalk membranes (red) is impaired in Crb mutants (right). Tepass/Macmillan

In the maturing fly eye, the apical domains and rhabdomeres (containing visual pigment) are in the center of each cluster of photoreceptor cells. The rhabdomere is linked by the stalk membrane to the adherens junctions (AJs), which separate the apical and basolateral membranes.

The new studies by Ulrich Tepass (University of Toronto, Toronto, Canada) and colleagues and Kwang-Wook Choi (Baylor College of Medicine, Houston, TX) and colleagues demonstrate that the human and fly versions of Crumbs localize to corresponding domains of the apical plasma membrane in the stalk of the fly photoreceptor and the inner segment of mammalian photoreceptors. In this region, Crb appears to be carrying out two functions. First, it cements the AJs together so they form a continuous band from the top to the bottom of the eye. Crb is ideally suited for this job because, based on its function in determining cell polarity; it is already in the correct, apical part of the eye where the AJs are needed. Second, Crb contributes to the elongation of the rhabdomere during the rapid growth that drives expansion toward the base of the retina. Tepass hypothesizes that this may be a consequence of Crb binding a web of ß_H-Spectrin, which then reduces the general level of endocytosis.

Overexpression of corresponding domains of fly Crb and human CRB1 had similar effects, suggesting that the function of the protein is conserved between the species, despite marked differences in the light receptors. Further study of the system in flies may provide clues about why the retinal degeneration seen in humans is a relatively slow process.

References:

Izaddoost, S., et al. 2002. Nature. 10.1038/nature720.

Pellikka, M., et al. 2002. Nature. 10.1038/nature721.

Nicole LeBrasseur

lebrasn{at}rockefeller.edu

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This Article Full Text (PDF, 191K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                            What's this?