10 A niversary of IIMCB

involved in defence against pathogens. In human genomes
there are two genes encoding CHORD containing proteins,
melusin and CHP-1. Melusin is present exclusively in
cardiac and skeletal muscles. It protects the heart from the
consequences of chronic aortic hypertension. The highest
level of CHP-1 is found in the brain but it is also present in
other tissues. The biological role of this protein remains
unknown but it is believed that CHP-1 might be a chaperon
responsible for maintaining proper cell function under stress
conditions. CHP-1 gene is regulated by HSF-1 (Heat Shock
Factor 1) and the protein interacts directly with the major
cellular chaperon, HSP90 (Sbroggiò et al., FEBS Lett, 2008).
We characterize CHP-1 expression pattern in rodents brains
under normal conditions and after insults causing stress. We
are studying the CHP-1 chaperon activity, using an in vitro
assay which is based on monitoring of an aggregation of
a heat liable proteins, citrate synthase. We are interested in
changes of subcellular distribution of CHP-1 under different
stress conditions. We also investigated the susceptibility of
cells with different CHP-1 levels (overexpression and RNAi)
to stress induced apoptosis (Michowski et al., in preparation).
6. Studies on cyclin-dependent kinase 5 involvement in
pathogenesis of Alzheimer’s disease (Aleksandra Szybińska
in collaboration with Aleksandra Wysłouch-Cieszyńska and
Prof. Michał Dadlez from laboratory of Mass Spectrometry,
Institute of Biochemistry and Biophysics PAN)
Cyclin-dependent kinase 5 in complex with p35 protein
has brain-specific activity and is known to play an important
role in a variety of neuronal processes in both developing
brains and adult brains. In an adult brain, cdk5 via its
interactions with different synaptic, cytoskeletal and cellular
adhesion proteins as well as NMDA receptors and calcium
channels, is involved in synaptic plasticity, memory and
learning processes impaired in Alzheimer’s disease. It was
shown recently that in AD patients, the brain expression and
activation of cdk5 is upregulated. That upregulation results
in MAP tau overphosphorylation together with that caused
by GSKβ kinase. Other consequences of cdk5 activity
impairment regarding AD are poorly understood. Using
the proteomics methods we analyse protein expression
and modifications in synaptosomes of transgenic mice,
AD models bearing human mutated presenilin 1 and APP
genes. Using different methods of samples of preparation
and fractionation, we identified almost over 1500
synaptic proteins. Preliminary statistical analysis of mass
spectrometry data obtained from wild type and transgenic
animals synaptosomes revealed a set of differential
proteins, some of which are known to be dysregulated in
Alzheimer’s disease but expression changes of some other
proteins are being shown for the first time. Additionally,
we have made an attempt to increase the efficiency of
identification of membrane proteins which are known to be
underrepresented in different proteomic analyses.
Fig. 4. β-catenin occupancy along Cacna1G promoter - chromatin immunoprecipitation (ChIP). Real Time PCR analysis of the ChIP products. The
results are shown as fold enrichment above background (IgG) (author: Marta Wiśniewska).
Laboratory of Neurodegeneration 45