Abc of the ABC Transporters in Human Organism
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Summary:
Plant caspases and their function during programmed cell death in
plants were presented in this article. Programmed Cell Death is a
process during which cells die in a strictly controlled manner.
Caspases are cysteine proteases which execute apoptosis in animal
cells. They hydrolyze peptide bonds after aspartic acid residues.
Plants possess some groups of enzymes which resemble caspases: vacuolar
processing enzymes, saspases, phytaspases, metacaspases, but do not
fulfill basic criterions that allow considering them as caspases.
Vacuolar processing enzymes (VPE) belong to cysteine proteases and
possess caspase activity. Saspases and phytaspases, although having
serine in the active center, possess also caspase activity.
Metacaspases do not have caspase activity. VPE are localized in the
vacuole and are responsible for breaking tonoplanst. Saspases and
phytaspases act both inside and outside of the cell. Saspases activate
a cascade of proteolytic enzymes, whereas phytaspases can directly
degrade proteins in the cell. Metacaspases directly degrade important
cell components, probably in the cytosol. Plant caspases, in spite of
superficial similarities to animal caspases, are only their functional
equivalents, therefore we use quotation mark. They degrade important
for cell structures or proteins, leading to cell death.
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Cancer Diagnostics and Treatment in Molecular and Immunohistochemical View – Where Are We?
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Key Role of Omega-3 and Omega-6 Fatty Acids in Human Biology; Crawford’s Predictive Theory of Evolution
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Quercetin in Anticancer Therapy
Key words: quercetin, bioavailability, cancers, apoptosis, cell cycle, chemotherapy
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Mechanisms of Lead Toxicity
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Summary: Specific
tissue response to endogenic and synthetic glucocorticoids (GCs) is
controlled at different levels of cell function: target gene
transcriptions, glucocorticoid receptor (GR) protein translation, GR
activation and translocation to the nucleus. Molecular mechanism of GR
action is related to genomic regulation of gene expression, i.e.,
transactivation or transrepression of steroid-sensitive genes via
interaction with gene promoter, influence on mRNA stability of some
proteins, interaction with numerous transcription factors, microRNAs as
well as influence on chromatin remodeling. Non-genomic mechanism of GR
action is connected with activation of secondary transmitters and
signaling pathways via nuclear and membrane receptors associated with
ion channels as well as through interaction with tyrosine and
serine/threonine kinases and adaptor proteins. Molecular
mechanism of GK activity may determine the proper or lack of response
on GK in the treatment of many autoimmune and inflammatory diseases
including asthma, multiple sclerosis, Crohn diseases or POChP.
Keywords: glucocorticoid receptor, chromatin remodeling, inflammation, transcription factors, MAPK signaling pathway
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The Role of Heat Shock Transcription Factor 1 in Carcinogenesis
Summary: Heat Shock Factor 1 (HSF1) is a transcription factor activated during environmental stress, which leads to HSPs (Heat Shock Proteins) expression. HSPs serve as molecular chaperons in the refolding of proteins, and in enhancing cellular resistance to apoptosis, therefore having important cytoprotective functions. In many tumor types, HSF1 and HSPs are overproduced. HSF1 can support the neoplastic transformation as well as enhance survival of tumor cells in their microenvironment, by modulating many signal transduction pathways that control cell growth, proliferation, apoptosis, metabolism and cell motility. HSF1 can cause genomic instability by overriding cell cycle checkpoints. Heat Shock Elements (HSEs), recognized by HSF1, are present not only in HSP promoters but also in ABCB1 (MDR1) gene, coding for P-glycoprotein, which actively removes drugs from the cell. In accordance with this observation, HSF1 would provide a selective advantage to tumor cells during cancer therapy. The normal cytoprotective role of HSF1 is highly undesirable in cancer, and validates it as a new, important therapeutic target. |
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Multifunctional Germin Protein and Germin-Like Proteins in Plants
Summary: Germins and germin-like proteins constitute a large and very diverse family of ubiquitous plant proteins. They belong to the cupin superfamily of proteins which name comes from the domain of b-barrel structure (from the Latin Cupa - small barrel). It is evolutionary conserved domain localized in C- terminal end. It consists of two amino acid sequence motifs: 1 and 2, described as the ‘germin box’. Cupin domain determines the high thermal stability, which is come out of the presence of disulphide bridges and the glycosylation degree. The presence of domain cupin suitable these proteins resistance to the protease protein. Germins occur in two isoforms gf-2.8 and gf-3.8 encoded by the gf-2.8 and gf-3.8 genes, active during the embryos germination of all economically important crops. In both genes there are regions without introns, which encode 224 amino acids, showing 90% homology. It is interesting that in the 5’ region of gf-2.8 gene; there are two sequence motifs characteristic of auxin genes. There has been distinguished six subfamilies of germin-like proteins with different enzymatic activity. There has been recognized a lot of germin-like proteins involved in plant defense responses against pathogens and pests. Defensive activity of GLP was found in apoplast which are expressed and react with the cell wall by facilitating an early response to pathogen attack. Particularly important are GLPs with oxalate oxidase activity, because they lower levels of oxalate, which is a virulence factor produced by several fungal pathogens. Transcription of the genes encoding germins and oxalate oxidase activity is stimulated by fungal infections and some metal ions. Wheat germin also have enormous potential for commercial applications because of the previously mentioned unusual resistance to proteases, high stability and resistance to heat. |
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The Application of Stem Cells in Medicine
Summary: The number of carried out scientific studies concerning various applications of stem cells in medicine has increased in recent years. In the literature numerous new reports present developments in applications of stem cells not only in hematology but also in treatment of inter alia chronic and genetic diseases, diabetes, neurological disorders, skin burns, spinal cord after mechanical injury or regeneration of damaged heart muscle and many others. The widespread application of stem cells in medicine raises ethical controversies. In this paper we review the literature concerning positive and negative aspects of stem cells applications in research aimed particularly at obtaining blood cells. |
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