|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
First published online 22 April 2008
doi: 10.1242/jcs.015958
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Short Report |

1 National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, UK
2 Department of Cell Biology, University Medical Center Utrecht (UMCU), Rm G02.525, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
Author for correspondence (e-mail: jvincent{at}nimr.mrc.ac.uk)
Accepted 3 March 2008
Summary
Two lipids (palmitate and palmitoleic acid) are appended onto Wnt proteins. It has been suggested that palmitate is required for signalling, whereas palmitoleic acid is necessary for progression through the secretory pathway. By mutating the relevant amino acids, we have investigated how these adducts contribute to the secretion and signalling activity of Wingless, the main Drosophila member of the Wnt family. Analysis of Wingless with a Cysteine 93 to Alanine mutation ([C93A]Wingless) shows that palmitoylation is essential for signalling activity in vivo (as well as in cultured cells). Moreover, without palmitate, Wingless fails to reach the surface of imaginal disc cells and, as electron microscopy (EM) analysis suggests, appears to accumulate in the endoplasmic reticulum (ER). Artificial targeting of palmitate-deficient Wingless to the plasma membrane does not rescue signalling activity. Therefore, palmitate at C93 has a dual role: in secretion and signalling. From our analysis of [S239A]Wingless, which lacks a conserved residue shown to be acylated in Wnt3a, we infer that palmitoleic acid is not, as previously suggested, absolutely required for secretion. Nevertheless, this mutant has poor signalling activity, suggesting that palmitoleic acid contributes significantly to signalling. We suggest that the overall level of lipidation affects signalling activity.
Key words: Wingless, Drosophila, Secretion, Acylation, Morphogen
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
Related articles in JCS:
This article has been cited by other articles:
![]() |
F. Hamaratoglu, K. Basler, and M. Affolter Confronting Morphogen Gradients: How Important Are They for Growth? Sci. Signal., October 27, 2009; 2(94): pe67 - pe67. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Zhang, D. Chen, and Z. Wang Analyses of mental dysfunction-related ACSl4 in Drosophila reveal its requirement for Dpp/BMP production and visual wiring in the brain Hum. Mol. Genet., October 15, 2009; 18(20): 3894 - 3905. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. A. Baena-Lopez, X. Franch-Marro, and J.-P. Vincent Wingless Promotes Proliferative Growth in a Gradient-Independent Manner Sci. Signal., October 6, 2009; 2(91): ra60 - ra60. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. M. Cadigan and M. Peifer Wnt Signaling from Development to Disease: Insights from Model Systems Cold Spring Harb Perspect Biol, August 1, 2009; 1(2): a002881 - a002881. [Abstract] [Full Text] [PDF] |
||||
![]() |
In vivo role of lipid adducts on Wingless Development, June 1, 2008; 135(11): e1 - e1. [Full Text] |
||||