Influence of a mitochondrial genetic defect on capacitative calcium entry and mitochondrial organization in the osteosarcoma cells

AbstractEffects of T8993G mutation in mitochondrial DNA (mtDNA), associated with neurogenical muscle weakness, ataxia and retinitis pigmentosa (NARP), on the cytoskeleton, mitochondrial network and calcium homeostasis in human osteosarcoma cells were investigated. In 98% NARP and ρ0 (lacking mtDNA) cells, the organization of the mitochondrial network and actin cytoskeleton was disturbed. Capacitative calcium entry (CCE) was practically independent of mitochondrial energy status in osteosarcoma cell lines. The significantly slower Ca2+ influx rates observed in 98% NARP and ρ0, in comparison to parental cells, indicates that proper actin cytoskeletal organization is important for CCE in these cells

p66Shc Aging Protein in Control of Fibroblasts Cell Fate

Reactive oxygen species (ROS) are wieldy accepted as one of the main factors of the aging process. These highly reactive compounds modify nucleic acids, proteins and lipids and affect the functionality of mitochondria in the first case and ultimately of the cell. Any agent or genetic modification that affects ROS production and detoxification can be expected to influence longevity. On the other hand, genetic manipulations leading to increased longevity can be expected to involve cellular changes that affect ROS metabolism. The 66-kDa isoform of the growth factor adaptor Shc (p66Shc) has been recognized as a relevant factor to the oxygen radical theory of aging. The most recent data indicate that p66Shc protein regulates life span in mammals and its phosphorylation on serine 36 is important for the initiation of cell death upon oxidative stress. Moreover, there is strong evidence that apart from aging, p66Shc may be implicated in many oxidative stress-associated pathologies, such as diabetes, mitochondrial and neurodegenerative disorders and tumorigenesis. This article summarizes recent knowledge about the role of p66Shc in aging and senescence and how this protein can influence ROS production and detoxification, focusing on studies performed on skin and skin fibroblasts

Involvement of Rac/Cdc42/PAK pathway in cytoskeletal rearrangements

The p21-activated kinases (PAKs) are serine/threonine protein kinases interacting with small GTPases - Rac and Cdc42. PAKs are found in most eukaryotes and play an evolutionarily conserved role in many cellular processes. Six human PAKs have been identified, and based on homology, they can be classified into two groups. This review focuses specifically on the role of Rac/Cdc42 regulated PAKs in maintaining and remodeling cytoskeletal structure in various organisms. A list of PAKs substrates and binding partners implicated directly and indirectly in cytoskeletal reorganization is presented. Also perturbations of the Rac/Cdc42/PAK pathway leading to tumorigenesis and neurodegenerative diseases are reviewed

Secular entourage of Queen Jadwiga Anjou

Tematem pracy jest świeckie i urzędnicze otoczenie królowej Jadwigi Andegaweńskiej. Analizie została poddana sytuacja rodzinno-społeczna i geograficzna urzędników oraz losy ich karier. W pracy został również poruszony problem bliższego i dalszego otoczenia królowej. Badanie zostało przeprowadzone metodą prozopograficzną.The theme of this thesis is secular entourage of Queen Jadwiga Anjou. Situation family has been subjected analysis -social and geographic officers and fates of their career. At the work moved issue was also the closest and farthest retinue of the queen. The study was conducted by prozopography method

Clerical entourage of Queen Jadwiga Andegaweńska

Praca dotyczy otoczenia duchownego królowej Jadwigi Andegaweńskiej. Jej celem było ukazanie tej grupy społecznej z jej pochodzeniem społeczno-geograficznym, wykształceniem, karierą kościelną oraz kontaktami z władczynią.The main aim of the thesis was to present social group clerical entourage of Queen Jadwiga of Anjou. Social and geographic origin of this group, their education, career and contacts with the Queen has been analyzed in detail

The regulatory role of mitochondria in capacitative calcium entry

AbstractCapacitative regulation of calcium entry is a major mechanism of Ca2+ influx into electrically non-excitable cells, but it also operates in some excitable ones. It participates in the refilling of intracellular calcium stores and in the generation of Ca2+ signals in excited cells. The mechanism which couples depletion of intracellular calcium stores located in the endoplasmic reticulum with opening of store-operated calcium channels in the plasma membrane is not clearly understood. Mitochondria located in close proximity to Ca2+ channels are exposed to high Ca2+ concentration, and therefore, they are able to accumulate this cation effectively. This decreases local Ca2+ concentration and thereby affects calcium-dependent processes, such as depletion and refilling of the intracellular calcium stores and opening of the store-operated channels. Finally, mitochondria modulate the intensity and the duration of calcium signals induced by extracellular stimuli. Ca2+ uptake by mitochondria requires these organelles to be in the energized state. On the other hand, Ca2+ flux into mitochondria stimulates energy metabolism. To sum up, mitochondria couple cellular metabolism with calcium homeostasis and signaling