QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 20 September 2006
doi: 10.1242/dev.02563

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: dev.02563v1 133/20/4109    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fairbank, P. D. Articles by Wallingford, J. B. Search for Related Content PubMed PubMed Citation Articles by Fairbank, P. D. Articles by Wallingford, J. B.

Shroom2 (APXL) regulates melanosome biogenesis and localization in the retinal pigment epithelium

Pamela D. Fairbank¹, Chanjae Lee¹, Avegiyel Ellis^1,*, Jeffrey D. Hildebrand², Jeffrey M. Gross^1,3 and John B. Wallingford^1,3,

¹ Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA.
² Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
³ Institute for Neuroscience, University of Texas, Austin, TX 78712, USA.

Author for correspondence (e-mail: wallingford{at}mail.utexas.edu)

Accepted 3 August 2006

Shroom family proteins have been implicated in the control of the actin cytoskeleton, but so far only a single family member has been studied in the context of developing embryos. Here, we show that the Shroom-family protein, Shroom2 (previously known as APXL) is both necessary and sufficient to govern the localization of pigment granules at the apical surface of epithelial cells. In Xenopus embryos that lack Shroom2 function, we observed defects in pigmentation of the eye that stem from failure of melanosomes to mature and to associate with the apical cell surface. Ectopic expression of Shroom2 in naïve epithelial cells facilitates apical pigment accumulation, and this activity specifically requires the Rab27a GTPase. Most interestingly, we find that Shroom2, like Shroom3 (previously called Shroom), is sufficient to induce a dramatic apical accumulation of the microtubule-nucleating protein -tubulin at the apical surfaces of naïve epithelial cells. Together, our data identify Shroom2 as a central regulator of RPE pigmentation, and suggest that, despite their diverse biological roles, Shroom family proteins share a common activity. Finally, because the locus encoding human SHROOM2 lies within the critical region for two distinct forms of ocular albinism, it is possible that SHROOM2 mutations may be a contributing factor in these human visual system disorders.

Key words: Shroom, Shroom2, Retina, RPE, APXL, Melanosome, Ocular albinism

This article has been cited by other articles:

				N.-O. Chimge, A. V. Makeyev, F. H. Ruddle, and D. Bayarsaihan Identification of the TFII-I family target genes in the vertebrate genome PNAS, July 1, 2008; 105(26): 9006 - 9010. [Abstract] [Full Text] [PDF]

				T. Nishimura and M. Takeichi Shroom3-mediated recruitment of Rho kinases to the apical cell junctions regulates epithelial and neuroepithelial planar remodeling Development, April 15, 2008; 135(8): 1493 - 1502. [Abstract] [Full Text] [PDF]

				R. Etournay, I. Zwaenepoel, I. Perfettini, P. Legrain, C. Petit, and A. El-Amraoui Shroom2, a myosin-VIIa- and actin-binding protein, directly interacts with ZO-1 at tight junctions J. Cell Sci., August 15, 2007; 120(16): 2838 - 2850. [Abstract] [Full Text] [PDF]

				C. Lee, H. M. Scherr, and J. B. Wallingford Shroom family proteins regulate {gamma}-tubulin distribution and microtubule architecture during epithelial cell shape change Development, April 1, 2007; 134(7): 1431 - 1441. [Abstract] [Full Text] [PDF]