Vol. 1 No. 2 June 1996

Volume 1 (1996) pp 119-128
Title BILE FLOW, VESICULAR TRAFFICKING, AND INTERACTIONS OF CYTOSKELETON WITH THE CANALICULAR DOMAIN OF HEPATOCYTE PLASMA MEMBRANE
Authors S.Pikula1,* and J. Bandorowicz-Pikula2
Abstract Liver is an epithelial organ which removes many substances from the blood, metabolizes them, and secretes back into circulation or directly into the bile. Liver parenchymal cells (hepatocytes) are involved in the overall detoxification of the organism through the bile. These highly polarized cells are unique among others due to the domain structure of their plasma membrane, organization of their cytoskeleton connected to the canalicular region of plasmalemma, and the specific distribution of various transport system involved in detoxification phase III. In this mini-review the possible influence of canalicular motility modulated by cytoskeleton on the bile flow is discussed. In addition, the role of annexins, calcium- and phospholipid-binding proteins exhibiting high expression level in liver, in vesicular trafficking leading to the transport of some of biliary components is also postulated.
Address and Contact Information 1Department of Cellular Biochemistry
2Department of Cell Biology, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw,
Poland
*Corresponding author. Tel: (+4822) 6598571 ext.347; Fax: (+4822) 225342
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 129-135
Title In VITRO INTERACTION OF C27-STEROLS WITH THE ERYTHROCYTE MEMBRANES DEPENDS ON THE STEROL STRUCTURE AND CONCENTRATION
Authors A.V.Tuganova and A.V.Kotsyuruba
Abstract  
Address and Contact Information Institute of Biochemistry National Academy of Science of Ukraine 252030 Kiev, Ukraine
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 137-144
Title ROLE OF MEMBRANE SKELETON IN DISCONTINUOUS RED BLOOD CELL SHAPE TRANSFORMATIONS
Authors A.Iglic1,2, S.Svetina1,3 and B. Zeks1,3
Abstract A possible physical interpretation of a discontinuous transition between different red blood cell shapes is given. The red blood cell membrane is considered to consist of the bilayer part and the underlying membrane skeleton. By taking into consideration that the stable cell shape corresponds to the minimum of the membrane energy, that consists of the bilayer and skeleton elastic energies and of the bilayer-skeleton interaction energy, it is shown that aggregation of the skeleton can cause the discontinuous cell shape transformation from a shape with the bilayer completely underlaid with the skeleton to the shape involving a spherical parent cell with completely underlaid bilayer and spherical daughter vesicles without the skeleton.
Address and Contact Information 1 Institute of Biophysics, Medical Faculty
2 Faculty of Electrical Engineering
3 J. Stefan Institute, University of Ljubljana, SI 61105 Ljubljana, Slovenia
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 145-149
Title ras ONCOGENE PRODUCT p21 EXPRESSION IN ADENOCARCINOMA OF HUMAN ENDOMETRIUM
Authors R Miturski, A. Semczuk and J.A. Jakowicki
Abstract ras-encoded p21 protein expression was investigated immunohistochemically in 10 specimens of human endometrial adenocarcinoma. The control group consisted of 5 proliferative endometrium slides. The analysis was performed by using the biotin-streptavidin-peroxidase AEC detection system. An immunohistochemical histologic H-score according to Nyholm et al. was calculated in a semiquantitative fashion incorporating intensity and distribution of staining. Adenocarcinoma glandular cells stained positively in 6 out of 10 specimens (n=6; H-score 0.71; range 0.3-1.15), whereas adenocarcinoma stromal cells exhibited a reddish-brown colour in all specimens analyzed (n=10; H-score 0.83; range 0.3-1.5). Only one out of 5 proliferative endometrium slides stained positively for ras p21 (H-score 0.3). Our observations suggest that in human endometrial adenocarcinomas not only glandular but also stromal cells reacted strongly with monoclonal antibody NCC-RAS-001 raised against ras p21 protein. Enhanced ras p21 expression adenocarcinoma stromal cells in comparison with adenocarcinoma glandular cells may suggest that stromal cells are involved strongly in the neoplasm formation.
Address and Contact Information II Department of Gynaecologic Surgery University School Medicine, 8 Jaczewski Street, 20-095 Lublin, Poland
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 151-161
Title ROLE OF BAND 3 AND GLYCOPHORIN C IN THE MAINTENANCE OF THE SHAPE AND MECHANICAL PROPERTIES OF THE HUMAN RED BLOOD CELL
Authors M.A.Staricoff and M.J.A.Tanner
Abstract Recent studies involving the anion transport protein AE1 (syn. band 3) and glycophorin C in their normal and variant states have demonstrated that these cytoskeletal associated transmembrane proteins play an important role in maintaining the shape and mechanical properties of the human red blood cell. Mutations in the band 3 molecule can lead to a variable outcome on the integrity and physical properties of the erythrocyte. The band 3 Memphis variants and band 3 high transport, for example, appear to have no deleterious effects on the mechanical properties of the red cell whereas total loss of anion transport activity and increased plasma-membrane rigidity is observed with South-east asian ovalocytes. The mechanisms by which mutant band 3 molecules affect the final properties of the cell appear to result from a missasembled membrane domain and an alteration in the protein's association with the cytoskeleton. Cell shape changes are commonly observed in band 3 mutant cells, manifested as spherocytes, choreoacanthocytes or acanthocytes. Leach phenotype cells, which lack glycophorins C and D and protein p55, when stripped of protein 4.1, have a much reduced affinity for the binding of purified protein 4.1 than normal protein 4.1 depleted cells. Recent studies have shown that protein 4.1 and protein p55 associate directly and on different sites with glycophorin C and that the glycophorin C-protein 4.1-protein p55 complex is required to maintain the shape and mechanical properties of the red cell.
Address and Contact Information Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 163-169
Title HIGH DENSITY LIPOPROTEIN AND LOW DENSITY LIPOPROTEIN - MEDIATED CHANGES IN CULTURED HUMAN SKIN FIBROBLASTS
Authors Z.Jozwiak1, D.Szosland2 and B.Rozga1
Abstract We investigated the effect of native and modified high density lipoprotein (HDL) and low density lipoprotein (LDL) on the viability and the membrane fluidity of normal and diabetic fibroblasts. Under experimental conditions, HDL did not affect the cultured normal cells. Incubation of HDL with diabetic fibroblasts resulted in a negligible decrease in the cell viability and induced and increase in the lipid fluidity at surface of the cell membranes. LDL at the higher concentration reduced the viability both normal and diabetic fibroblasts and also enhanced the fluidity of membrane lipids. The above changes in the fluidity of fibroblast membranes were observed mainly in the presence of native and oxidized lipoproteins and are connected with the differences in the structure of cell membranes and nature of the cytotoxicity of LDL and HDL..
Address and Contact Information 1University of Lodz, Department of Thermobiology, 90-237 Lodz
2Department of Gastroenterology and Metabolic Disorders, Medical Academy of Lodz, Poland
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 171-176
Title POLYPEPTIDES IMMUNOLOGICALLY RELATED TO SPECTRIN ARE PRESENT IN BACTERIAL CELLS
Authors B.Bisikirska, M. Lorenz, M. Nietubyc and A.F.Sikorski *
Abstract Spectrin and spectrin-like proteins were found in almost all animal and protozoan cells. Moreover, several reports indicate their presence also in plants. We found that polypeptides reacting with anti-spectrin antibodies are also present in bacteria such as Escherichia coli and Halobacterium salinarium. In Escherichia coli only polypeptide(s) reacting with antibodies directed against alpha subunit could be detected while in Halobacterium salinarium polypeptides reactive with antibodies directed against both subunits (alpha and beta) were found. Our data may suggest a presence of spectrin-related polypeptides in early stages of evolution.
Address and Contact Information University of Wroclaw, Institute of Biochemistry, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
* Corresponding author E-mail: afsbc@microb.uni.wroc.pl Tel. and fax: (+48 71) 25-29-30
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 177-187
Title REGULATION OF TRANSMEMBRANE SIGNALING BY THE MEMBRANE SKELETON IN PLATELETS
Authors J.E.B.Fox
Abstract The cytoskeleton is involved in regulating motile events and properties of the plasma membrane. However, it is now clear that the cytoskeleton can bind signaling molecules, recruiting them adjacent to their substrates, and/or inducing their activation. In platelets, the membrane is lined by a skeleton which in turn associates with membrane glycoproteins. Signaling molecules associate with the membrane skeleton in unstimulated platelets and preliminary evidence suggests that components of the membrane skeleton may become phosphorylated on tyrosine residues when platelets are activated. As adhesion receptors bind their ligands, the membrane skeleton becomes more tightly associated with the underlying actin filaments and additional signaling molecules are recruited to the integrin-cytoskeletal complexes. This article describes the evidence for association of signaling molecules with the platelet cytoskeleton and discusses the potential significance of such interactions.
Address and Contact Information Cleveland Clinic Foundation, Cleveland, OH 44195, U.S.A.
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 189-198
Title MODULATION OF HEMOLYTIC PROPERTIES OF RESORCINOLIC LIPIDS BY DIVALENT CATIONS
Authors M.Stasiuk and A.Kozubek
Abstract
Address and Contact Information Institute of Biochemistry, Wroclaw University, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
[Rozmiar: 1332 bajtów]

Volume 1 (1996) pp 199-203
Title STUDYING PROTEIN-DNA BINDING BY DYNAMIC LIGHT SCATTERING
Authors N.Zh.Zhelev1, R.S.Buckle1, D.Snyder2 and P.J.Marsh1
Abstract Light scattering experiments were undertaken to study binding of the Max transcription factor to its E-box DNA recognition sequence. Translational diffusion coefficients were measured and the average hydrodynamic radii (Rh) of complexes calculated using the Stokes-Einstein equation. We detected both dimerization of Max and the formation of a stable complex with its E-box DNA target. These results demonstrate the applicability of Dynamic Light Scattering for measuring protein-DNA interactions.
Address and Contact Information 1Randall Institute, King's College London, 26-29 Drury Lane, London, WC2B 5RL
2Protein Solutions, Inc 1500 Avon Street Extended, Charlottesville, VA 22902
[Rozmiar: 1332 bajtów]