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dictyNews Volume 21 Number 09
Dicty News
Electronic Edition
Volume 21, number 9
September 19, 2003
Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu.
Back issues of Dicty-News, the Dicty Reference database and other
useful information is available at dictyBase - http://dictybase.org.
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Special Note to the Dictyostelium community
============================================
An order sheet for the Special Dictyostelium Issue (including a CD with
movies) of the Journal of Muscle Research and Cell Motility can be found
in the 'News' section at http://dictybase.org.
The price of 60 Euro is a special offer that I have negotiated with Kluwer
for the Dictyostelium community.
Dietmar Manstein
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Abstracts
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Identification and Characterization of Novel Calcium-binding Proteins of
Dictyostelium and Their Spatial Expression Patterns during Development
Haruyo Sakamoto, Keiko Nishio, Mariko Tomisako, Hidekazu Kuwayama,
Yoshimasa Tanaka, Isao Suetake, Shouji Tajima, Satoshi Ogihara, Barrie
Coukell, and Mineko Maeda
Develop., Growth, Differ. (in press)
Five putative Ca2+-binding proteins, CBP5, 6, 7, 8 and 9, having EF-hand
motifs were found by searching the Dictyostelium cDNA database.
45Ca2+-overlay experiments revealed that four of them (excluding CBP9) are
real Ca2+-binding proteins. Northern blot analysis revealed that the genes
encoding CBP5, 6, 7 and 8 are all developmentally regulated. In situ
hybridization analyses revealed that spatial expression of these genes was
regulated in several different manners. CBP1, 2, 3, 5, 6 and 7 are expressed
in prespore cells in the slug stage. Transcripts of the genes for CBP1 and 5
are enriched in prestalk subtype PstO cells. On the other hand, CBP4 is
expressed predominantly in PstO cells. CBP8 is evenly expressed at a very
low level throughout the whole slug. Such distinct spatial expression
patterns suggest that the CBPs might be involved in morphogenesis and might
have their own roles either in prespore or in prestalk cell differentiation
of Dictyostelium.
Submitted by: Mineko Maeda [mmaeda@bio.sci.osaka-u.ac.jp]
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A structural model for actin-induced nucleotide release in myosin
Thomas F. Reubold#, Susanne Eschenburg#, Andreas Becker#, , F.Jon Kull#,¤ &
Dietmar J. Manstein#,¦
#Max-Planck Institut fr medizinische Forschung, Abteilung Biophysik,
Jahnstr. 29, D-69120 Heidelberg, Germany, ¤Dartmouth College Department of
Chemistry, 6128 Burke Laboratory, Hanover, NH 03755, USA, ¦Institut fr
Biophysikalische Chemie, OE 4350, Medizinische Hochschule Hannover,
Carl-Neuberg-Str. 1, 30623 Hannover, Germany
Nature Structural Biology, in press
Myosins are molecular motor proteins that harness the chemical energy stored
in ATP in order to produce directed force along actin filaments. The
detailed mechanism of force production is dependent on synchronized action
of the various structural and functional elements of the myosin motor
domain, and remains poorly understood. Complex communications pathways link
the catalytic nucleotide binding region, the structures responsible for
force amplification, and the actin binding domain of myosin1. We have
crystallized the motor domain of myosin II in a new conformation in which
switch I and switch II, conserved loop structures involved in nucleotide
binding, have moved away from the binding pocket, resulting in a
nucleotide-free state. These movements are linked to a rearrangement of the
actin binding domains, which illuminate a previously unobserved
communication pathway between the nucleotide binding site and the actin
binding region, explain the reciprocal relationship between actin and
nucleotide affinity and suggest a new mechanism for product release in
myosin family motors.
Submitted by: Dietmar J. Manstein [manstein@bpc.mh-hannover.de]
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[End Dicty News, volume 21, number 9]
