Copy Link
Add to Bookmark
Report
dictyNews Volume 29 Number 12
dictyNews
Electronic Edition
Volume 29, number 12
November 2, 2007
Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.
Back issues of dictyNews, the Dicty Reference database and other
useful information is available at dictyBase - http://dictybase.org.
=========
Abstracts
=========
Competition between targeting signals in hybrid proteins provides
information on their relative in vivo affinities for subcellular compartments
Christian Schmauch, Markus Maniak
Zellbiologie und CINSaT, Universitaet Kassel, Kassel, Germany
Eur. J. Cell Biol., in press
After their translation and folding in the cytoplasm, proteins may be imported
into an organelle, associate with a membrane, or rather become part of large,
highly localised cytoplasmic structures such as the cytoskeleton. The
protein's localisation is governed by the binding-strength to its immediate
target, such as an import receptor for an organelle or a major component of
the cytoskeleton e.g. actin. We have experimentally provided a set of
actin-binding proteins with competing targeting information and expressed
them at various concentrations to analyse the strength of the signal that
governs their subcellular localisation. Our microscopic observations
indicate that organellar sorting signals override the targeting preference
of most cytoskeletal proteins. Among these signals, the nuclear localisation
signal of SV40 is strongest, followed by the oligomerised PHB domain that
targets vacuolin to the endosomal surface, and finally the tripeptide SKL
mediating transport into the peroxisome. The actin-associated protein coronin,
however, can only be misled by the nuclear localisation signal. Interestingly,
the targeting behaviour of this model set of hybrid proteins in living
Dictyostelium amoebae correlates surprisingly well with the affinities of
their constituent signals derived from in vitro experiments conducted in
various other organisms. Accordingly, this approach allows estimating the in
vivo affinity of a protein to its target even if the latter is not known, as
in the case of vacuolin.
Submitted by: Markus Maniak [maniak@uni-kassel.de]
==============================================================
[End dictyNews, volume 29, number 12]
