Copy Link
Add to Bookmark
Report
dictyNews Volume 25 Number 05
Dicty News
Electronic Edition
Volume 25, number 5
September 2, 2005
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 Dicty-News, the Dicty Reference database and other
useful information is available at dictyBase - http://dictybase.org.
=============
Abstracts
=============
Paxillin is required for cell-substrate adhesion, cell sorting and slug
migration during Dictyostelium development
Tanya Bukahrova, Gertrud Weijer, Leonard Bosgraaf, Dirk Dormann,
Peter J. van Haastert, Cornelis J Weijer
Journal of Cell Science, in press
Paxillin is a key regulatory component of focal adhesion sites, implicated
in controlling cell-substrate interactions and cell movement. We analyse
the function of a Dictyostelium discoideum paxillin homologue, PaxB, which
contains 4 highly conserved LD and 4 LIM domains, but lacks two
characteristic tyrosine residues, that form the core of vertebrate
SH2 binding domains. PaxB is expressed during growth and all stages of
development, but expression peaks during slug formation. Using a paxB-gfp
knockin strain we show the existence of focal adhesions and characterise
their dynamics. During multicellular development PaxB is not only found in
focal adhesions at the cell-substrate interface, but also in the tips of
filopodial structures predominantly located at the trailing ends of cells.
paxB- strains are less adhesive to the substrate, they can aggregate but
multicellular development from the mound stage onwards is severely impeded.
paxB- strains are defective in proper celltype proportioning, cell sorting,
slug migration and form defective fruiting bodies. Mutation of a conserved
JNK phosphorylation site, implicated in the control of cell migration,
does not have any major effects on cell sorting, slug migration or
morphogenesis in Dictyostelium. PaxB does not appear to function redundantly
with its closest relative Lim2 (paxA), which when deleted also results in a
mound arrest phenotype. However analysis of paxA- and paxB- single and
double null mutants suggest that PaxB may act upstream of Lim2.
Submitted by: Kees Weijer [c.j.weijer@dundee.ac.uk]
-----------------------------------------------------------------------------
Isolation and synthesis of a new aromatic compound, brefelamide, from
Dictyostelium cellular slime molds and its inhibitory effect on proliferation
of astrocytoma cells.
Kikuchi H, Saito Y, Sekiya J, Okano Y, Saito M, Nakahata H, Kubohara Y &
Oshima, Y.
Graduate School of Phamaceutical Sciences, Tohoku Univiersity, Japan. etc.
J. Org. Chem., In press.
We have explored the diversity of secondary metabolites produced by cellular
slime molds to examine the possible use of such cellular slime molds as a
resource for novel drug development. A new aromatic amide, brefelamide, was
isolated from methanol extracts of the fruiting bodies of Dictyostelium
brefeldianum and D. giganteum. The structure of brefelamide was determined
by spectral means including EIMS and 1H and 13C NMR. The total synthesis of
brefelamide was carried out to confirm the structure and obtain sufficient
samples for performing biological evaluation. Interestingly, the compound
inhibited the cellular proliferation of 1321N1 human astrocytoma cells.
Submitted by: Yuzuru Kubohara [kubohara@showa.gunma-u.ac.jp]
==============================================================================
[End Dicty News, volume 25, number 5] 
