scholarly journals Current Understanding of the Structure and Function of Pentapeptide Repeat Proteins

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 638
Author(s):  
Ruojing Zhang ◽  
Michael A. Kennedy
Keyword(s):  
Current Knowledge ◽  
Three Dimensional ◽  
Type I ◽  
Type Iv ◽  
Repeat Proteins ◽  
Biochemical Function ◽  
And Function ◽  
Life On Earth ◽  
Multicellular Organisms ◽  
Pcc 7120

The pentapeptide repeat protein (PRP) superfamily, identified in 1998, has grown to nearly 39,000 sequences from over 3300 species. PRPs, recognized as having at least eight contiguous pentapeptide repeats (PRs) of a consensus pentapeptide sequence, adopt a remarkable structure, namely, a right-handed quadrilateral β-helix with four consecutive PRs forming a single β-helix coil. Adjacent coils join together to form a β-helix “tower” stabilized by β-ladders on the tower faces and type I, type II, or type IV β-turns facilitating an approximately −90° redirection of the polypeptide chain joining one coil face to the next. PRPs have been found in all branches of life, but they are predominantly found in cyanobacteria. Cyanobacteria have existed on earth for more than two billion years and are thought to be responsible for oxygenation of the earth’s atmosphere. Filamentous cyanobacteria such as Nostoc sp. strain PCC 7120 may also represent the oldest and simplest multicellular organisms known to undergo cell differentiation on earth. Knowledge of the biochemical function of these PRPs is essential to understanding how ancient cyanobacteria achieved functions critical to early development of life on earth. PRPs are predicted to exist in all cyanobacteria compartments including thylakoid and cell-wall membranes, cytoplasm, and thylakoid periplasmic space. Despite their intriguing structure and importance to understanding ancient cyanobacteria, the biochemical functions of PRPs in cyanobacteria remain almost completely unknown. The precise biochemical function of only a handful of PRPs is currently known from any organisms, and three-dimensional structures of only sixteen PRPs or PRP-containing multidomain proteins from any organism have been reported. In this review, the current knowledge of the structures and functions of PRPs is presented and discussed.

scholarly journals Much More Than a Scaffold: Cytoskeletal Proteins in Neurological Disorders

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 358 ◽  
Author(s):  
Diana C. Muñoz-Lasso ◽  
Carlos Romá-Mateo ◽  
Federico V. Pallardó ◽  
Pilar Gonzalez-Cabo
Keyword(s):  
Neurological Disorders ◽  
Actin Filaments ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Neurological Diseases ◽  
Three Dimensional ◽  
Cytoskeletal Proteins ◽  
Dimensional Lattice ◽  
New Treatments ◽  
And Function

Recent observations related to the structure of the cytoskeleton in neurons and novel cytoskeletal abnormalities involved in the pathophysiology of some neurological diseases are changing our view on the function of the cytoskeletal proteins in the nervous system. These efforts allow a better understanding of the molecular mechanisms underlying neurological diseases and allow us to see beyond our current knowledge for the development of new treatments. The neuronal cytoskeleton can be described as an organelle formed by the three-dimensional lattice of the three main families of filaments: actin filaments, microtubules, and neurofilaments. This organelle organizes well-defined structures within neurons (cell bodies and axons), which allow their proper development and function through life. Here, we will provide an overview of both the basic and novel concepts related to those cytoskeletal proteins, which are emerging as potential targets in the study of the pathophysiological mechanisms underlying neurological disorders.

Macromolecular constituents of basement membranes: a review of current knowledge on their structure and function

1983 ◽  
Vol 61 (8) ◽  
pp. 942-948 ◽  
Author(s):  
Paul G. Scott
Keyword(s):  
Type Iv Collagen ◽  
Current Knowledge ◽  
Heparan Sulphate ◽  
Structural Features ◽  
Structure And Function ◽  
Basement Membranes ◽  
Type Iv ◽  
Type V ◽  
And Function ◽  
Additional Form

Macromolecules which appear to be integral constituents of basement membranes include type IV collagen, the glycoprotein laminin, and heparan sulphate proteoglycan. Another glycoprotein, fibronectin, may occupy an intermediate position between some lining cells and their basement membranes but is not, however, restricted to this location. An additional form of collagen, genetic type V which differs significantly from type IV collagen in structure, appears to be associated with some basement membranes, possibly linking them to underlying connective tissue. The main structural features of each of these macromolecules, as presently understood, are reviewed here as a background to the experimental papers in this "mini-symposium."

scholarly journals Study On The Application of Preoperative Three-Dimensional CT Angiography of Perigastric Arteries In Laparoscopic Radical Gastrectomy

2022 ◽  
Author(s):  
Peng Liu ◽  
Wenbin Yu ◽  
Meng Wei ◽  
Danping Sun ◽  
Xin Zhong ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Blood Loss ◽  
Three Dimensional ◽  
Classification Model ◽  
Type I ◽  
Radical Gastrectomy ◽  
Type Ii ◽  
Type Iii ◽  
Type Iv ◽  
Type V

Abstract Objection: To investigate the clinical value and significance of preoperative three-dimensional computerized tomography angiography (CTA) in laparoscopic radical gastrectomy for gastric cancer.Methods: The clinical data were analyzed retrospectively from 214 gastric cancer patients. We grouped according to whether to perform CTA. The gastric peripheral artery was classified according to CTA images of patients in the CTA group, and we compared and analyzed the difference of the data between the two groups.Results: The celiac trunk was classified according to Adachi classification: Type I (118/125, 94.4%),Type II (3/125, 2.4%),Type III (0/125, 0%),Type IV (1/125, 0.8%),Type V (2/125, 1.6%),Type VI (1/125, 0.8%).Hepatic artery classification was performed according to Hiatt classification standard:Type I (102/125, 81.6％),Type II (9/125, 7.2%),Type III (6/125, 4.8%),Type IV (2/125, 1.6%),Type V (3/125, 2.4%),Type VI (0, 0%),Others (3/125, 2.4%).And this study combined vascular anatomy and clinical surgical risk to establish a new splenic artery classification model. It was found that the operation time and estimated blood loss in the CTA group were significantly lower than those in the non-CTA group. In addition, the blood loss in the CTA group combined with ICG (Indocyanine Green) labeled fluorescence laparoscopy was significantly less than that in the group without ICG labeled. Conclusion: Preoperative CTA can objectively evaluate the vascular course and variation of patients, and then avoid the risk of operation, especially in combination with ICG labeled fluorescence laparoscopy, can further improve the quality of operation.

Drosophila PS integrins recognize vertebrate vitronectin and function as cell-substratum adhesion receptors in vitro

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 1007-1016 ◽  
Author(s):  
S. Hirano ◽  
K. Ui ◽  
T. Miyake ◽  
T. Uemura ◽  
M. Takeichi
Keyword(s):  
Cell Attachment ◽  
Collagen Type I ◽  
Matrix Proteins ◽  
Type I ◽  
Rgd Peptides ◽  
Drosophila Cell ◽  
Type Iv ◽  
And Function

Using the Drosophila cell line MLDmBG-1, a monoclonal antibody aBG-1 that can inhibit not only cell clumping but also cell spreading was generated. This antibody immunoprecipitates a complex of molecules consisting of a major 120 × 10(3) Mr and other components. To characterize the 120 × 10(3) Mr component, we purified it, generated antibodies to it, and cloned its cDNA. Sequencing of this cDNA suggests that the 120 × 10(3) Mr molecule is identical to PS beta, a beta chain of Drosophila integrins. The other components immunoprecipitated included two alpha chains of Drosophila integrins, PS1 alpha and PS2 alpha, as revealed using specific antibodies to these molecules. These suggest that aBG-1 recognizes the PS beta associated with PS1 alpha or PS2 alpha. However, immunostaining of embryos and larvae with aBG-1 showed that the staining pattern is similar to that for PS2 alpha but not for PS beta, suggesting that the antibody preferentially recognizes the PS beta associated with particular alpha chains in situ. We then attempted to characterize the ligands for these integrin complexes, using culture dishes coated with various vertebrate matrix proteins. These cells spread very well on dishes coated with vitronectin and, to a lesser extent, on those with fibronectin. This spreading was partially inhibited by aBG-1, but not by other control antibodies or RGD peptides. The cell attachment to these substrata was not affected by the antibody. The cells also can attach to dishes coated with laminin but without spreading, and this attachment was not inhibited by aBG-1. Furthermore, they do not attach to dishes coated with collagen type I, type IV, and fibrinogen. These results indicate that Drosophila PS integrins can recognize vertebrate vitronectin, and also fibronectin with a weaker affinity, at sites other than RGD sequences, and thus can function in cell-substratum adhesion.

scholarly journals Alphavirus-Induced Membrane Rearrangements during Replication, Assembly, and Budding

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 984
Author(s):  
Zeinab Elmasri ◽  
Benjamin L. Nasal ◽  
Joyce Jose
Keyword(s):  
Current Knowledge ◽  
Rna Replication ◽  
Type I ◽  
Type Ii ◽  
Fatal Disease ◽  
Structural Modifications ◽  
Host Interactions ◽  
Infected Cells ◽  
Membrane Type ◽  
And Function

Alphaviruses are arthropod-borne viruses mainly transmitted by hematophagous insects that cause moderate to fatal disease in humans and other animals. Currently, there are no approved vaccines or antivirals to mitigate alphavirus infections. In this review, we summarize the current knowledge of alphavirus-induced structures and their functions in infected cells. Throughout their lifecycle, alphaviruses induce several structural modifications, including replication spherules, type I and type II cytopathic vacuoles, and filopodial extensions. Type I cytopathic vacuoles are replication-induced structures containing replication spherules that are sites of RNA replication on the endosomal and lysosomal limiting membrane. Type II cytopathic vacuoles are assembly induced structures that originate from the Golgi apparatus. Filopodial extensions are induced at the plasma membrane and are involved in budding and cell-to-cell transport of virions. This review provides an overview of the viral and host factors involved in the biogenesis and function of these virus-induced structures. Understanding virus–host interactions in infected cells will lead to the identification of new targets for antiviral discovery.

3D Model of Thrombopoiesis.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1609-1609 ◽  
Author(s):  
Isabella Pallotta ◽  
Michael L. Lovett ◽  
David L. Kaplan ◽  
Alessandra Balduini
Keyword(s):  
Bone Marrow ◽  
Type I Collagen ◽  
Blood Platelets ◽  
Type I ◽  
Type Iv ◽  
Vascular Niche ◽  
Factor Type ◽  
And Function ◽  
Von Willebrand

Abstract Abstract 1609 Background. The mechanisms that regulate megakaryocytic (Mk) development within the bone marrow environment remain poorly understood. The underlying relationships between Mk maturation and bone marrow components are key factors in this process. Mk development occurs in a complex microenvironment where extracellular matrices are fundamental regulatory components. The first events occur in the osteoblastic niche and include commitment of the hemopoietic progenitor cell to Mk, arrest of proliferation and initiation of endomitosis. The second step is Mk maturation and is associated with rapid cytoplasm expansion and intense synthesis of proteins. Finally Mks, which migrate to the vascular niche, convert the bulk of their cytoplasm into multiple long processes called proplatelets that protrude through the vascular endothelium into the sinusoid lumen, where the platelets are released. Hypothesis. The hypothesis for the present work is that a complex in vitro 3D bone marrow-like environment can be used to gain fundamental mechanistic insight into cell signalling and matrix-cell interactions in the bone marrow niche related to Mk development. Methods. We propose the first 3D model for Mk function in the bone marrow environment, by refining a recently proposed bioreactor platform (Lovett et al., 2007). These bioreactors consist of 3 wells (10 mm × 15 mm × 5 mm) within a PDMS block (25 mm × 60 mm × 5 mm) which is plasma bonded to cover glass for imaging. Each bioreactor well was perfused by 23 G stainless steel needles, spanned by porous silk microtubes as blood vessel scaffolds (640 μm inner diameter), positioned approximately 500–750 μm from the bottom of the bioreactor and connected to tubing for media perfusion using a programmable syringe pump. These microtubes were prepared by dipping several times straight lengths of stainless steel wire into 10–14% (w/v) aqueous silk fibroin to obtain blood vessel scaffolds with a wall thickness of around 50 mm. Defined pore sizes of 6–8 μm were obtained by adding 6 w/t % poly(ethylene oxide) (PEO) to the silk fibroin. The perfused silk tubes comprised the vascular niche and were embedded within a cell-seeded hydrogel which comprises the osteoblastic niche. The silk microtubes were coated with a combination of fibrinogen, von Willebrand Factor, type IV collagen and SDF-1 alpha, to better establish the composition of the vascular niche. Control experiments were performed by coating silk microtubes with type I collagen. After staining human umbilical cord blood derived Mks, the cell suspension was added to the hydrogel and Mk migration was analyzed in a time-dependent manner using confocal microscopy analysis. Further, flow effluent through the vascular tubes in the bioreactor was collected at regular time intervals and platelet numbers and function were analyzed by flow cytometry and microscopy. Culture released platelets were counted as CD61+ events with the same scatter properties of human blood platelets. Results. Our results showed that Mks migrated towards the vascular microtube coated with Fibrinogen, von Willebrand Factor, type IV collagen and SDF-1. Mks were also able to complete their maturation in the proximity of the microtube by extending proplatelets. Interestingly, confocal microscopy analysis revealed that Mks were able to extend proplatelets through the vascular microtube wall and release CD61+ platelet-like particles inside the vascular microtube. Cytofluorimentric analysis demonstrated that the particles collected in the flow effluent of the vascular microtube were CD61+ cells with the same scatter properties of human peripheral blood platelets. Finally, upon coating with only type I collagen Mks did not migrate towards the vascular microtube or extend proplatelets to release platelets. Thus, by mimicking the relationship between Mks and the bone marrow environment, a model to reproduce the different steps of Mk development, such as Mk migration, proplatelet formation and platelet release, is established. This is a first significant step towards relevant systems for the study of these cellular processes in detail as well as toward potentially useful in vitro platelet production systems. Conclusions. In this work we developed a new 3D bone marrow system in vitro that could represent a new tool to understand the mechanistic basis for Mk development and function, and the diseases related to these cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Endoglin: An ‘Accessory’ Receptor Regulating Blood Cell Development and Inflammation

2020 ◽  
Vol 21 (23) ◽  
pp. 9247
Author(s):  
Steffen K. Meurer ◽  
Ralf Weiskirchen
Keyword(s):  
Endothelial Cells ◽  
Immune System ◽  
Immune Cells ◽  
Transforming Growth Factor ◽  
Current Knowledge ◽  
Vascular Lesions ◽  
Type I ◽  
And Function ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1) is a pleiotropic factor sensed by most cells. It regulates a broad spectrum of cellular responses including hematopoiesis. In order to process TGF-β1-responses in time and space in an appropriate manner, there is a tight regulation of its signaling at diverse steps. The downstream signaling is mediated by type I and type II receptors and modulated by the ‘accessory’ receptor Endoglin also termed cluster of differentiation 105 (CD105). Endoglin was initially identified on pre-B leukemia cells but has received most attention due to its high expression on activated endothelial cells. In turn, Endoglin has been figured out as the causative factor for diseases associated with vascular dysfunction like hereditary hemorrhagic telangiectasia-1 (HHT-1), pre-eclampsia, and intrauterine growth restriction (IUPR). Because HHT patients often show signs of inflammation at vascular lesions, and loss of Endoglin in the myeloid lineage leads to spontaneous inflammation, it is speculated that Endoglin impacts inflammatory processes. In line, Endoglin is expressed on progenitor/precursor cells during hematopoiesis as well as on mature, differentiated cells of the innate and adaptive immune system. However, so far only pro-monocytes and macrophages have been in the focus of research, although Endoglin has been identified in many other immune system cell subsets. These findings imply a functional role of Endoglin in the maturation and function of immune cells. Aside the functional relevance of Endoglin in endothelial cells, CD105 is differentially expressed during hematopoiesis, arguing for a role of this receptor in the development of individual cell lineages. In addition, Endoglin expression is present on mature immune cells of the innate (i.e., macrophages and mast cells) and the adaptive (i.e., T-cells) immune system, further suggesting Endoglin as a factor that shapes immune responses. In this review, we summarize current knowledge on Endoglin expression and function in hematopoietic precursors and mature hematopoietic cells of different lineages.

Use of antibodies in the study of protein structure and function in lung diseases

1991 ◽  
Vol 260 (2) ◽  
pp. L1-L12
Author(s):  
E. J. Miller ◽  
A. B. Cohen
Keyword(s):  
Lung Diseases ◽  
Current Knowledge ◽  
Function Analysis ◽  
Three Dimensional ◽  
Structure And Function ◽  
Protein Chemistry ◽  
Modern Biology ◽  
Protein Molecules ◽  
And Function ◽  
Structure Of Proteins

Proteins normally fold in a variety of three-dimensional structures. This variety of forms accounts for a multiplicity of functions. One of the major undertakings of modern biochemistry is to determine the structure of a given protein and in doing so learn about its function. Much of the effort in the field of protein chemistry is currently focused on defining areas or domains within the molecule that are responsible for its function. Antibodies specific for functional domains on a protein have been powerful tools in these studies and have provided a great deal of the current knowledge related to the location and function of well-defined structural areas within the protein molecules. The use of antibodies in the study of proteins has considerably advanced our knowledge of both the structure of proteins and their interaction with other molecules. In reviewing the use of antibodies for structure and/or function analysis, we have tried not only to review the techniques and applications involving antibodies but also to show how useful antibody reagents may be designed and prepared. In this review, some of the newer uses of antibodies in modern biology will be described, and a few illustrations of each will be provided.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

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