dictyNews
Electronic Edition
Volume 35, number 14
Nov 26, 2010
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Abstracts
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Dictyostelium dynamin B modulates cytoskeletal structures and
membranous organelles
Amrita Rai, Heike Noethe, Nikolay Tzvetkov, Elena Korenbaum,
Dietmar J. Manstein
Institut fuer Biophysikalische Chemie, OE 4350,
Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1,
30623 Hannover, Germany
Cellular and Molecular Life Sciences, in press
Dictyostelium discoideum cells produce five dynamin family proteins. Here,
we show that dynamin B is the only member of this group of proteins that is
initially produced as a preprotein and requires processing by mitochondrial
proteases for formation of the mature protein. Our results show that dynamin
B-depletion affects many aspects of cell motility, cell-cell and cell-surface
adhesion, resistance to osmotic shock, and fatty acid metabolism. The mature
form of dynamin B mediates a wide range and unique combination of functions.
Dynamin B affects events at the plasma membrane, peroxisomes, the
contractile vacuole system, components of the actin-based cytoskeleton, and
cell adhesion sites. The modulating effect of dynamin B on the activity of the
contractile vacuole system is unique for the Dictyostelium system. Other
functions displayed by dynamin B are commonly associated with either
classical or dynamin-related proteins.
Submitted by Dietmar Manstein [[log in to unmask]]
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Domain architecture of the DRpp29 protein and its interaction with the
RNA subunit of Dictyostelium discoideum RNase P
Vassiliki Stamatopoulou1, Chrisavgi Toumpeki1, Andreas Tzakos2,
Anastassios Vourekas1, and Denis Drainas1
1Department of Biochemistry, School of Medicine, University of Patras,
Greece.
2Department of Chemistry, Section of Organic Chemistry and Biochemistry,
University of Ioannina, Greece
Biochemistry in press
Dictyostelium discoideum nuclear RNase P is a ribonucleoprotein complex
that displays similarities with its counterparts from higher eukaryotes such as
the human enzyme, but at the same time it retains distinctive characteristics.
In the present study, we report the molecular cloning and interaction details
of DRpp29 and RNase P RNA, two subunits of the RNase P holoenzyme
from Dictyostelium discoideum. Electrophoretic mobility shift assays exhibited
that DRpp29 binds specifically to the RNase P RNA subunit, a feature that
was further confirmed by the molecular modeling of the DRpp29 structure.
Moreover, deletion mutants of DRpp29 were constructed in order to
investigate the domains of DRpp29 that contribute to and/or are responsible
for the direct interaction with the D. discoideum RNase P RNA. A eukaryotic
specific, lysine and arginine rich region was revealed, which seems to facilitate
the interaction between these two subunits. Furthermore, we tested the ability
of wild type and mutant DRpp29 to form active RNase P enzymatic particles
with the E. coli’s RNase P RNA.
Submitted by Denis Drainas [[log in to unmask]]
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[End dictyNews, volume 35, number 14]
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