This book presents a full spectrum of views on current approaches to modeling cell mechanics. The authors of this book come from the biophysics, bioengineering, and physical chemistry communities and each joins the discussion with a unique perspective on biological systems. Consequently, the approaches range from ﬁnite element methods commonly used in continuum mechanics to models of the cytoskeleton as a cross-linked polymer network to models of glassy materials and gels.
Palytoxin is a marine toxin responsible for a fatal type of poisoning in
humans named clupeotoxism, with symptoms such as neurologic distur-bances. It is believed that it binds to the Na
-ATPase from the extra-cellular side and modifies cytosolic ions; nevertheless, its effects on internal
cell structures, such as the cytoskeleton, which might be affected by these
initial events, have not been fully elucidated.
Much work has focused on the electrophysiological properties of transient
receptor potential channels. Recently, a novel aspect of importance
emerged: the interplay of transient receptor potential channels with the
cytoskeleton. Recent data suggest a direct interaction and functional reper-cussion for both binding partners.
Okadaic acid (OA) and its analogs, the dinophysistoxins, are potent inhibi-tors of protein phosphatases 1 and 2A. This action is well known to cause
diarrhea and gastrointestinal symptons when the toxins reach the digestive
tract by ingestion of mollusks. A less well-known effect of these group of
toxins is their effect in the cytoskeleton.
From previous observations, addition of the antibody
raised against the α6-integrin subunit in the GC culture
medium impairs cell-spreading on LN substratum and
induces the formation of clusters of rounded cells . It
can be hypothesized that changes in cell shape might be
responsible for all or part of the functional changes
observed in survival, proliferation and steroidogenesis of
Recent studies have established essential roles of protein kinase Ce in
signaling pathways controlling various functions of microfilaments and
intermediate filaments by modulating multiple cytoskeletal proteins. This
review summarizes recent progress in our understanding of the roles of
protein kinase Ce in the functions and signaling of microfilaments and
A variety of microbes manipulate the cytoskeleton of mammalian cells to
promote their internalization, motility and⁄or spread. Among such bacte-ria, enteropathogenic Escherichia coliand enterohemorrhagic Escherichia
coliare closely related pathogens that adhere to human intestinal cells and
reorganize the underlying actin cytoskeleton into ‘pedestals’.
Enterohemorrhagic and enteropathogenicEscherichia coliproduce various
effector proteins that are directly injected into the host-cell cytosol through
the type III secretion system. E. colisecreted protein (Esp)B is one such
effector protein, and affects host-cell morphology by reorganizing actin net-works.
Messenger RNA trafficking, which provides a mechanism for local protein
synthesis, is dependent on cis-acting sequences in the 3¢ untranslated
regions (3¢UTRs) of the mRNAs concerned acting together withtrans-act-ing proteins. The C-MYC transcription factor is a proto-oncogene product
involved in cell proliferation, differentiation and apoptosis. Localization of
c-myc mRNA to the perinuclear cytoplasm and its association with the
cytoskeleton is determined by a signal in the 3¢UTR.
In many laboratories, the requirement of microtubule-associated proteins
(MAPs) and the stabilization of microtubules for the elongation of neurites
has been intensively investigated, with controversial results being obtained.
We have observed that the neurite microtubules of Cath.a-differentiated
(CAD) cells, a mouse brain derived cell, are highly dynamic structures, and
so we analyzed several aspects of the cytoskeleton to investigate the molecu-lar causes of this phenomenon.
Human mitochondrial NAD(P)
-dependent malic enzyme (m-NAD-ME)
is a malic enzyme isoform with dual cofactor specificity, ATP inhibition
and substrate cooperativity. The determinant of ATP inhibition in malic
enzyme isoforms has not yet been identified.
Palytoxin is a marine toxin first isolated from zoanthids (genusPalythoa),
even though dinoflagellates of the genusOstreopsisare the most probable
origin of the toxin.Ostreopsishas a wide distribution in tropical and sub-tropical areas, but recently these dinoflagellates have also started to appear
in the Mediterranean Sea.
In recent years, many natural macrolactones have been found that display
toxicity against the actin cytoskeleton. Pectenotoxins are macrolactones
produced by species of the dinoflagellate genusDinophysis. They were ini-tially classified within the diarrheic shellfish poisoning group of toxins,
because of their co-occurrence and biological origin, but mice toxicity
assays demonstrated that pectenotoxins do not induce diarrheic symptoms.
To determine the reliability of applying these categories to specific song lyrics, two
observers independently classified the reproductive themes present in written versions of
the reproductively relevant phrases extracted from a representative sample of the Pop,
Country, and R&B songs. The number of phrases containing reproductive messages ranged
from 2 (“White Horse” and “Second Chance”) to 29 (“Baby By Me”) for a total of 219
reproductive phrases, with an average of 8.76 different reproductive references per song.
This book spans a variety of approaches to address the complex problem of Alzheimer´s
disease - what is the cause, is there a single pathogenetic pathways or are there many of
them, how can we address the whole clinical spectrum of the disease, how can the disease
be diagnosed early and reliable and which perspectives we have for prevention and treat‐
ment. The collection covers actual topics of interest for basic researcher, clinicians, epidemi‐
ologists and provides insight...
Recent developments/efforts to understand aspects of the brain function at the subneural
level are discussed. MicroTubules (MTs), protein polymers constructing the
cytoskeleton, participate in a wide variety of dynamical processes in the cell. Of special
interest to us is the MTs participation in bioinformation processes such as learning
and memory, by possessing a well-known binary error-correcting code [K1(13, 26, 5)]
with 64 words. In fact, MTs and DNA/RNA are unique cell structures that possess
a code system.
Aberrant regulation of protein kinases impairs normal cellular functioning
and may lead to disease. The protein kinase involved in the regulation of
the dynamics of the actin cytoskeleton, Rho-kinase (ROCK), phosphory-lates various substrates (e.g. myosin light chain, myosin phosphatase), caus-ing the formation of actin fibers and tension inside cells.
Migration of vascular smooth muscle cells (SMCs) from the media to intima constitutes a critical step in the development of proliferative vascular diseases. To elucidate the regulatory mechanism of vacular SMC motility, the roles of caldesmon (CaD) and its phosphorylation were investigated. Methods: We have performed Transwell migration assays, immunofluorescence microscopy, traction microscopy and cell rounding assays using A7r5 cells transfected with EGFP (control), EGFP-wtCaD or phosphomimetic CaD mutants, including EGFP-A1A2 (the two PAK sites Ser452...