Yes / Background: The receptor for activated C-kinase 1 (RACK1) is a conserved protein belonging to the WD40 repeat
family of proteins. It folds into a beta propeller with seven blades which allow interactions with many proteins. Thus
it can serve as a scaffolding protein and have roles in several cellular processes.
Results: We identified the product of the Dictyostelium discoideum gpbB gene as the Dictyostelium RACK1 homolog.
The protein is mainly cytosolic but can also associate with cellular membranes. DdRACK1 binds to phosphoinositides
(PIPs) in protein-lipid overlay and liposome-binding assays. The basis of this activity resides in a basic region located in
the extended loop between blades 6 and 7 as revealed by mutational analysis. Similar to RACK1 proteins from other
organisms DdRACK1 interacts with G protein subunits alpha, beta and gamma as shown by yeast two-hybrid, pulldown, and immunoprecipitation assays. Unlike the Saccharomyces cerevisiae and Cryptococcus neoformans RACK1
proteins it does not appear to take over Gβ function in D. discoideum as developmental and other defects were not
rescued in Gβ null mutants overexpressing GFP-DdRACK1. Overexpression of GFP-tagged DdRACK1 and a mutant
version (DdRACK1mut) which carried a charge-reversal mutation in the basic region in wild type cells led to changes
during growth and development.
Conclusion: DdRACK1 interacts with heterotrimeric G proteins and can through these interactions impact on
processes specifically regulated by these proteins. / This work was supported by the DFG and SFB670. TYR acknowledges support from the Professorinnen Program of the University of Cologne.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/17711 |
| Date | 28 February 2020 |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Published version |
| Rights | © 2014 Omosigho et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated., CC-BY |
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