Joanna ŚLIWA-DOMINIAK, Wiesław DEPTUŁA
The Role of TRIM Receptors in Immunity
Summary: Recently,
TRIM (tripartite motif-containing) proteins attrackted much attention.
These receptors constitute a large family of proteins involved in an
innate immunity and in a broad range of biological processes. Their
universality is conditioned by their diversity, differences in tissue
expression and cell localization. TRIMs have been classified into 9
families – C-I to C-IX, and additionally C-X and CXI have been
described recently. Numbers of TRIMPs vary in different animal species.
The most commonly described role of these receptors is their engagement
in retroviral infections, for example HIV, MLV or ALV. Many of TRIMs
are IFN-induced what makes them important in pathogen immunity.
Moreover, TRIMs are engaged in regulation of signaling pathways induced
by TLRs and RIG-I.
Key words: TRIM, receptors, proteins, immunity.
Key
words: adipose-derived mesenchymal stem cells, regeneration, differentiation,
immunomodulation, adipose tissue, medical application
[Postępy
Biologii Komórki 2011; 38: 549–558]
Agata MUŁA, Dominika NOWIS
The Variety of the Glucose Transporters
Summary:
Glucose serves as a main energy source for the majority of human cells.
It is ingested with food, absorbed in the digestive tract and
transported via blood to supply the whole body. Facilitated passive
intracellular glucose transport is mediated by GLUT (glucose
transporters) proteins while SGLT (sodium-glucose transport) proteins
participate in its active transport. GLUT and SGLT expression is
tissue-dependent and influenced by its role in carbohydrates
metabolism. Recently, there is a lot of evidence for increased GLUT
expression in cancer cells and the diagnostic implications of this
phenomenon. One may wonder that in the nearest future the knowledge of
the physiology and pathology of glucose transporters develops and
results in the discovery of novel diagnostic and therapeutic anticancer
procedures.
Key
words: glucose, glucose transporters, metabolism
[Postępy
Biologii Komórki 2011; 38: 559–580]
Robert SOBKOWIAK, Andrzej LESICKI
Cell Signaling Pathways Activated by Nicotine
Summary:
Nicotine is biologically active. It competes with acetylcholine for
binding to specific membrane receptors, so-called nicotinic cholinergic
receptors (nAChRs). They are widely expressed in the nervous system and
skeletal muscle. Nicotinic receptors are also present in many cell
types, e.g. epithelial, blood, and cancer cells. When nicotine binds to
the nAChRs, the conformation of the receptor subunits changes, opening
the receptor channel gate. This allows the influx of sodium and calcium
ions into the cell, leading to membrane depolarization. It results in
the activation of influx of calcium ions. These processes trigger a
cascade of signal-dependent calcium ions. A very significant role of
nicotinic receptor in the regulation of apoptosis, angiogenesis as well
as in cell division and migration has been recently shown. Nicotine
induces growth factors, such as BDNF, VEGF, TGF-a, HGF, VEGF-C, TGF-b,
PDGF and has a mitogenic effect on cancer cells. A key role in these
processes is played by a serine-threonine kinase Raf and extracellular
signal-regulated kinases ERK1-ERK2. Nicotine causes an increase in
survival of cancer cells through phosphorylation of serine/threonine
protein kinase Akt, which interacts with other proteins, and leads to
blockage of apoptosis. Recently it has been shown that nicotine
interferes with hormonal signaling. Under the influence of nicotine,
the levels of serotonin, dopamine, gamma-aminobutyric acid (GABA), and
epinephrine are significantly changed.
Key
words: nicotine, nicotinic receptor, cell signaling, calcium
[Postępy
Biologii Komórki 2011; 38: 581–596]
Magdalena JURZAK, Paweł ANTOŃCZAK, Katarzyna ADAMCZYK
Białko aktywujące fibroblasty a (FAPa) – udział w gojeniu tkanek i kancerogenezie
Summary: Białko aktywujące fibroblasty a (FAPa) nazywane także seprazą zaliczane jest do typu II integralnych białek błonowych. FAPa/sepraza zakotwiczona w błonie komórkowej wykazuje aktywność peptydazy serynowej i aktywność żelatynolityczną. FAPa
należy do podrodziny S9B post-prolilowych aminopeptydaz dipeptylowych
(dipeptylopeptydaz post-prolilowych) peptydaz serynowych. Do podrodziny
tej oprócz FAPa/seprazy należy także dipeptylopeptydaza IV (DPPIV). Aktywne FAPa
jest homodimerem o masie cząsteczkowej 170 kDa, w skład którego
wchodzą dwie podjednostki każda o masie cząsteczkowej 97 kDa. FAPa
może także tworzyć heteromeryczny aktywny kompleks enzymatyczny z
DPPIV. Oba kompleksy enzymatyczne mogą brać udział w proteolizie
składników macierzy pozakomórkowej (ECM). Oprócz
zdolności do enzymatycznej degradacji niektórych
komponentów macierzy pozakomórkowej, FAPa kontroluje
wzrost fibroblastów i interakcje pomiędzy nabłonkiem a
mezenchymą podczas embriogenezy, a także procesy naprawy tkanek i
kancerogenezy. Białko to jest indukowalnym antygenem ulegającym
selektywnej ekspresji na aktywowanych fibroblastach podczas
procesów gojenia tkanek, swoistych dla nowotworów
fibroblastach (CAFs), podczas tworzenia przerzutów raków
nabłonkowych oraz na komórkach niektórych
nowotworów złośliwych. Proces gojenia tkanek i kancerogenezy
wykazują pewne podobieństwa. Wiele czynników wzrostu, cytokin i
proteaz, które produkowane są przez komórki nowotworowe
podczas transformacji i progresji nowotworów, bierze udział w
procesach gojenia i włóknienia tkanek. FAPa
jest markerem miofibroblastów obecnych zarówno podczas
gojenia tkanek, procesów włóknienia czy procesu
nowotworzenia. Nadekspresja FAPa
jest także charakterystyczna dla keloidów (bliznowców),
łagodnych rozrostów nowotworowych tkanki łącznej, będących
konsekwencją nieprawidłowego procesu gojenia.
Key
words: Białko aktywujące fibroblasty a (FAPa),
sepraza, fibroblasty, miofibroblasty, fibroblasty związane z
nowotworami (CAFs), metaloproteinazy macierzy pozakomórkowej (MMPs),
żelatynazy, gojenie tkanek, włóknienie, kancerogeneza
[Postępy
Biologii Komórki 2011; 38: 597–612]
Mirosława FERENS-SIECZKOWSKA
Muscular Dystrophies Due to Disorders in Sarcolemmal and Basal Lamina Protein
Summary:
Muscular cell integrity is assured by a number of proteins of
different structure, function and localization. Their defective
synthesis of genetic background results in muscular dystrophies. In
these diseases progressive damage of skeletal muscle leads to
disability, and in some cases affection of respiratory muscles may be a
cause of early death. There is no doubt now that proper muscle function
demands undisturbed collaboration of a great number of proteins,
located inside the cell as well as in sarcolemma and extracellular
matrix. This collaboration ensures appropriate indispensable
communication of the muscle cells with their external environment.
Molecular background is well known for the most common Duchenne
muscular dystrophy and Bethlem myopathy, both resulting from a damage
of dystrophin. Less is known about sarcolemmal and extracellular matrix
proteins. Defects in collagen VI and laminin, proteins responsible for
a proper anchoring of the cell in extracellular matrix, result in
Ullrich muscular dystrophy, Bethlem myopathy and merosin-dependent
muscular dystrophy MDC1A. Among proteins localized in sarcolemma,
defects resulting in muscular dystrophies were found in integrins and a
complex of sarcoglycans, four proteins responsible for stabilization of
dystrophin-glycoprotein complex in the cell membrane. A special group
of muscular dystrophies called dystroglycanopathies is a result
of defective glycosylation of a-dystroglycan. Uncovering the
molecular background of muscular dystrophies brings a hope for novel
therapies, creating molecular by-passes omitting defective proteins and
limiting disease progress and patients disability.
Key
words:
muscular dystrophy, basal lamina, dystroglycan, sarcoglycan, integrin,
laminin, collagen, dystrophin glycoprotein complex
[Postępy
Biologii Komórki 2011; 38: 613–628]
Piotr MRÓWKA, Eliza GŁODKOWSKA-MRÓWKA
Structure, Function and Role of Peroxisome Proliferator-Activated Receptor-Gamma – PPARg
Summary: Peroxisome proliferator-activated receptor-gamma (PPARg)
is one of the most intensively studied nuclear receptors of the last
two decades. The receptor owe its popularity to pleiotropic actions on
many important physiologic processes of single cells and whole
organisms such as energy homeodynamic regulation, control of glucose
and lipid metabolism, proliferation, differentiation, apoptosis,
inflammation or angiogenesis. Beside natural ligands some synthetic
agonists, antagonists and modulators of PPARg
are already known. This give us an opportunity to specific influence
the processes that receptor is regulating. Currently synthetic PPARg ligands,
thiazolidinediones are used for glucose control in patients with type 2
diabetes mellitus, but possibilities of full control of receptor
actions lead to much greater expectations. We are writing to recount
structure, actions and functions of PPARg and its possible applications in future medicine.
Key
words: PPARg, nuclear receptor, thiazolidinedione, diabetes mellitus type 2, rosiglitazone, pioglitazone
[Postępy
Biologii Komórki 2011; 38: 629–652]
Łukasz PIJANOWSKI, Elżbieta KOŁACZKOWSKA, Magdalena CHADZIŃSKA
Neutrophil Extracellur Traps (NET) – New Neutrophil Strategy to Combat Pathogens
Summary: Neutrophils
are one of the main types of effector cell engaged in the innate immune
response and comprise first line of defense against pathogens. At the
inflammatory site the cells eliminate pathogens and then die by
apoptosis. It was commonly recognized that neutrophils utilize two ways
to fight pathogens: phagocytosis and degranulation. However, in 2004 it
was discovered that neutrophils can also eliminate infectious agents by
formation of Neutrophil Extracellular Traps
(NET) that capture and kill microorganisms. They are composed of
decondensated chromatin to which specific proteins from the
neutrophilic granules are attached. NETs are extracelularly released
where they immobilize pathogens and secure their contact with
antibacterial molecules. To date only some mechanisms of NET formation
are described but it is decisively established that reactive oxygen
species formed by the NADPH oxidase pathway are critical for this
process. It was also reported that the release of NETs might be
directly induced by pathogens or indirectly by platelets that firstly
interact with microbes and subsequently with neutrophils. Altogether
the published data suggest that NETs are important for pathogen
elimination, however, their excessive production and/or removal might
lead to abnormalities and development of severe diseases.
Keywords: neutrophils, neutrophil extracellular traps, phagocytosis, degranulation, NADPH oxidase, reactive oxygen species
[Postępy
Biologii Komórki 2011; 38: 653–672]
Magdalena TURCZYN
ABC of Flower Architecture
Summary:
In recent years, the mechanisms of the origin and development of a
flower, which is a characteristic structure of angiosperms, became one
of the most intensively studied problems in modern evolutionary
studies. Two decades ago, the research of two independent scientific
groups, led by E. Coen and E. Meyerowitz on Anthirrhinum majus and Arabidopsis thaliana
flowers respectively, resulted in a model of the genetic regulation
of the successive whorls (sepals, petals, stamens and carpels)
development within the flower, called ABC model. This model assumes
that the characteristic whorl phenotype depends on the interaction of
three classes of homeotic genes. The expression of the class A genes
alone in the outermost whorl is responsible for the sepal formation.
Interaction of the genes from the A and B classes in the second whorl
and from B and C classes in the third whorl results in formation of the
petal crown and stamens, respectively. The carpels develop as a result
of the C class genes activity which are expressed exclusively in the
inner whorl. Further research revealed that the additional classes of
genes, D and E, are necessary for the proper ovary formation (D class
genes) and the full functionality of other ABC genes (E class
genes). Almost all the genes of the ABC model belong to the
MADS-box family. Their classification is based on a gene structure,
namely on the presence of four domains: the conservative MADS domain,
intervening (I), the typical of plant keratin-like (K) and the
C-terminal domain. Initially, the ABC model was proposed for eudicots
only, and was widely studied for them. However, it appeared to be a
very good tool for the analysis of the monocot flower architecture,
too. Research on rice, wheat and corn confirmed the presence and
functioning of the ABC genes in parts homologous to the eudicot flower.
Furthermore, the analysis of orchid flowers provided the evidence that
the combinations of different gene classes together with the presence
of paralogous genes within the class are responsible for the identity
of the elements and can significantly alter the phenotype of the
structure. The ABC model is the basis on which the appearance of many
unique structures within the flowers, especially in basal angiosperms,
has been explained. One of the theories, called „sliding
boundary”, suggests that the shift of the expression borders of
the class B genes is responsible for undifferentiated perianth and
explains the origin of e.g. petalody the observed phenomenon, in Magnolia stellata.
MADS-box genes have been discovered in different organisms, including
seed plants, ferns, mosses and algae. This suggests an early
evolutionary emergence of genes of the ABC model. Multiple duplications
of the genome in the course of plant evolution coupled with the changes
in the flower morphology, required specialization of the new orthologs
which gained in turn new roles/functions. The successive gene
duplications can be traced directly in the plant phylogenetic tree: for
instance, the first known B class gene duplication occurred at the time
of separation of magnoliids, the basal angiosperms, from a common
tree. The ABC model describes one of the mechanisms in plants,
which interacting with other developmental programs results in the wide
morphological diversity of flowers. The ABC model provides a new tool
to test phylogenetic relationships between plants and generates new
insight into plant evolution.
Key
words: ABC model, homeotic genes, MADS-box genes, flower architecture, basal angiosperms, magnoliids
[Postępy
Biologii Komórki 2011; 38: 673–684]
Ilona KOPERA-SOBOTA, Barbara BILIŃSKA
The Role of the Cell Junctions and Regulation of their Function in Mammalian Testis
Summary:T:
Spermatogenesis is a very complex process that involves an array of
cellular and biochemical events, collectively culminating in the
formation of haploid spermatids from diploid spermatogonia. It is
widely accepted that germ cell differentiation requires endocrine
regulation by gonadotropins and steroid hormones, a local control
through paracrine/autocrine factors, and, importantly, cell-cell
interactions via specialized cell junctions. These structures
participate in the intercellular communication and coordination of cell
metabolism. Moreover, cell junctions are known to mediate stable
adhesion throughout spermatogenesis and create a specialized
environment necessary for germ cell development and movement. The
purpose of this review was to demonstrate the molecular structure of
testicular cell junctions and their involvement in the regulation of
spermatogenesis. Moreover, we discussed recent findings relating to the
role of androgens in the regulation of cell junction dynamics in testis.
Key
words: cell junctions, testis, blood-testis barrier, ectoplasmic specialization, androgens
[Postępy
Biologii Komórki 2011; 38: 685–711]
