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 Abnormal Glomerular Basement Membrane Laminins in Murine, Canine, and Human Alport Syndrome: Aberrant Laminin α2 Deposition Is Species Independent

2001 ◽  
Vol 12 (2) ◽  
pp. 252-260
Author(s):  
CLIFFORD E. KASHTAN ◽  
YOUNGKI KIM ◽  
GEORGE E. LEES ◽  
PAUL S. THORNER ◽  
ISMO VIRTANEN ◽  
...  
Keyword(s):  
Alport Syndrome ◽  
Type Iv Collagen ◽  
Critical Role ◽  
Basement Membranes ◽  
Type Iv ◽  
Normal Human ◽  
Composition Structure ◽  
Type V ◽  
And Function ◽  
Laminin Α2

Abstract. Kidneys from mice, dogs, and humans with X-linked and autosomal-recessive forms of Alport syndrome were examined by immunofluorescence for expression of laminin α, β, and γ chains using monospecific antibodies. Laminin α2 chain was absent from glomerular basement membranes (GBM) in normal human, murine, and canine kidneys but was abnormally deposited in Alport GBM, regardless of species or inheritance pattern. In murine and canine Alport kidneys, laminin α2 seems to be deposited as part of both laminin-2 (α2β1γ1) and laminin-4 (α2β2γ1) but as part of only laminin-4 in human Alport kidneys. GBM laminin α2 chain deposition was not observed in a variety of non-Alport human glomerulopathies. This finding adds to the list of proteins that are aberrantly deposited in Alport GBM as a consequence of the absence of the α3, α4, and α5 chains of type IV collagen: (1) type IV collagen α1 and α2 chains, (2) type V collagen, (3) type VI collagen, and most recently (4) the laminin α2 chain and (5) the laminin α1 and β1 chains in mice and dogs. These findings emphasize further the critical role played by the α3, α4, and α5 chains of type IV collagen in establishing and maintaining the composition, structure, and function of mature GBM.

scholarly journals Characterization of muscle epimysium, perimysium and endomysium collagens

1984 ◽  
Vol 219 (3) ◽  
pp. 1017-1026 ◽  
Author(s):  
N Light ◽  
A E Champion
Keyword(s):  
Connective Tissue ◽  
Sodium Dodecyl Sulphate ◽  
Type Iv Collagen ◽  
Sodium Dodecyl ◽  
Basement Membranes ◽  
Type Iii Collagen ◽  
Type I ◽  
Type V Collagen ◽  
Type Iv ◽  
Type V

In the past it has been proven difficult to separate and characterize collagen from muscle because of its relative paucity in this tissue. The present report presents a comprehensive methodology, combining methods previously described by McCollester [(1962) Biochim. Biophys. Acta 57, 427-437] and Laurent, Cockerill, McAnulty & Hastings [(1981) Anal. Biochem. 113, 301-312], in which the three major tracts of muscle connective tissue, the epimysium, perimysium and endomysium, may be prepared and separated from the bulk of muscle protein. Connective tissue thus prepared may be washed with salt and treated with pepsin to liberate soluble native collagen, or can be washed with sodium dodecyl sulphate to produce a very clean insoluble collagenous product. This latter type of preparation may be used for quantification of the ratio of the major genetic forms of collagen or for measurement of reducible cross-link content to give reproducible results. It was shown that both the epimysium and perimysium contain type I collagen as the major component and type III collagen as a minor component; perimysium also contained traces of type V collagen. The endomysium, the sheaths of individual muscle fibres, was shown to contain both type I and type III collagen as major components. Type V collagen was also present in small amounts, and type IV collagen, the collagenous component of basement membranes, was purified from endomysial preparations. This is the first biochemical demonstration of the presence of type IV collagen in muscle endomysium. The preparation was shown to be very similar to other type IV collagens from other basement membranes on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and was indistinguishable from EHS sarcoma collagen and placenta type IV collagen in the electron microscope after rotary shadowing.

scholarly journals Hemicentin mediated type IV collagen assembly strengthens juxtaposed basement membrane linkage

2021 ◽  
Author(s):  
Claire A Gianakas ◽  
Daniel P Keeley ◽  
William Ramos-Lewis ◽  
Kieop Park ◽  
Ranjay Jayadev ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Fluorescent Proteins ◽  
Structure And Function ◽  
Egg Laying ◽  
Matrix Proteins ◽  
Type Iv ◽  
Seam Cell ◽  
Specialized Form ◽  
And Function

Basement membrane (BM) matrices surround and separate most tissues. However, through poorly understood mechanisms, BMs of adjacent tissues can also stably link to support organ structure and function. Using endogenous knock-in fluorescent proteins, conditional RNAi, optogenetics, and quantitative live imaging, we identified matrix proteins mediating a BM linkage (B-LINK) between the uterine utse and epidermal seam cell BMs in Caenorhabditis elegans that supports the uterus during egg-laying. We found that hemicentin is secreted by the utse and promotes fibulin-1 assembly to jointly initiate the B-LINK. During egg-laying, however, both proteins decline in levels and are not required for B-LINK maintenance. Instead, we discovered that hemicentin also promotes type IV collagen assembly, which accumulates to high levels during egg-laying and sustains the B-LINK during the mechanically active egg-laying period. This work reveals mechanisms underlying BM-BM connection maturation and identifies a crucial function for hemicentin and fibulin-1 in initiating attachment and type IV collagen in strengthening this specialized form of tissue linkage.

scholarly journals Structural and functional analysis of tomato sterol C22 desaturase

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Laura Gutiérrez-García ◽  
Montserrat Arró ◽  
Teresa Altabella ◽  
Albert Ferrer ◽  
Albert Boronat
Keyword(s):  
Catalytic Domain ◽  
Transmembrane Domain ◽  
Current Knowledge ◽  
Complex Mixture ◽  
Structural Features ◽  
Structure And Function ◽  
Cell Fractionation ◽  
Globular Domain ◽  
And Function ◽  
Functional Components

Abstract Background Sterols are structural and functional components of eukaryotic cell membranes. Plants produce a complex mixture of sterols, among which β-sitosterol, stigmasterol, campesterol, and cholesterol in some Solanaceae, are the most abundant species. Many reports have shown that the stigmasterol to β-sitosterol ratio changes during plant development and in response to stresses, suggesting that it may play a role in the regulation of these processes. In tomato (Solanum lycopersicum), changes in the stigmasterol to β-sitosterol ratio correlate with the induction of the only gene encoding sterol C22-desaturase (C22DES), the enzyme specifically involved in the conversion of β-sitosterol to stigmasterol. However, despite the biological interest of this enzyme, there is still a lack of knowledge about several relevant aspects related to its structure and function. Results In this study we report the subcellular localization of tomato C22DES in the endoplasmic reticulum (ER) based on confocal fluorescence microscopy and cell fractionation analyses. Modeling studies have also revealed that C22DES consists of two well-differentiated domains: a single N-terminal transmembrane-helix domain (TMH) anchored in the ER-membrane and a globular (or catalytic) domain that is oriented towards the cytosol. Although TMH is sufficient for the targeting and retention of the enzyme in the ER, the globular domain may also interact and be retained in the ER in the absence of the N-terminal transmembrane domain. The observation that a truncated version of C22DES lacking the TMH is enzymatically inactive revealed that the N-terminal membrane domain is essential for enzyme activity. The in silico analysis of the TMH region of plant C22DES revealed several structural features that could be involved in substrate recognition and binding. Conclusions Overall, this study contributes to expand the current knowledge on the structure and function of plant C22DES and to unveil novel aspects related to plant sterol metabolism.

scholarly journals Structural and Functional Analysis of Tomato Sterol C22 Desaturase

2020 ◽  
Author(s):  
Laura Gutiérrez-García ◽  
Montserrat Arró ◽  
Teresa Altabella ◽  
Albert Ferrer ◽  
Albert Boronat
Keyword(s):  
Catalytic Domain ◽  
Transmembrane Domain ◽  
Current Knowledge ◽  
Complex Mixture ◽  
Structural Features ◽  
Structure And Function ◽  
Cell Fractionation ◽  
Globular Domain ◽  
Essential Components ◽  
And Function

Abstract Background: Sterols are essential components of eukaryotic cells that modulate membrane biophysical properties and function. Plants produce a complex mixture of sterols, among which β-sitosterol, stigmasterol, campesterol, and cholesterol in some Solanaceae, are the most abundant species. Many reports have shown that the stigmasterol to β-sitosterol ratio changes during plant development and in response to stresses, suggesting that it may play a role in the regulation of these processes. In tomato (Solanum lycopersicum), changes in the stigmasterol to β-sitosterol ratio correlate with the induction of the only gene encoding sterol C22-desaturase (C22DES), the enzyme specifically involved in the conversion of β-sitosterol to stigmasterol. However, despite the biological interest of this enzyme, there is still a lack of knowledge about several relevant aspects related to its structure and function.Results: In this study we report the subcellular localization of tomato C22DES in the endoplasmic reticulum (ER) based on confocal fluorescence microscopy and cell fractionation analyses. Modeling studies have also revealed that C22DES consists of two well-differentiated domains: a single N-terminal transmembrane-helix domain (TMH) anchored in the ER-membrane and a globular (or catalytic) domain that is oriented towards the cytosol. Although TMH is sufficient for the targeting and retention of the enzyme in the ER, the globular domain may also interact and be retained in the ER in the absence of the N-terminal transmembrane domain. The observation that a truncated version of C22DES lacking the TMH is enzymatically inactive revealed that the N-terminal membrane domain is essential for enzyme activity. The in silico analysis of the TMH region of plant C22DES revealed several structural features that could be involved in substrate recognition and binding.Conclusions: Overall, this study contributes to expand the current knowledge on the structure and function of plant C22DES and to unveil novel aspects related with plant sterol metabolism.

scholarly journals Structure and Function of the CFTR Chloride Channel

1999 ◽  
Vol 79 (1) ◽  
pp. S23-S45 ◽  
Author(s):  
DAVID N. SHEPPARD ◽  
MICHAEL J. WELSH
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Channel ◽  
Atp Hydrolysis ◽  
Current Knowledge ◽  
Structure And Function ◽  
Binding Domains ◽  
Transporter Family ◽  
Membrane Spanning ◽  
And Function ◽  
R Domain

Sheppard, David N., and Michael J. Welsh. Structure and Function of the CFTR Chloride Channel. Physiol. Rev. 79 , Suppl.: S23–S45, 1999. — The cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ABC transporter family that forms a novel Cl− channel. It is located predominantly in the apical membrane of epithelia where it mediates transepithelial salt and liquid movement. Dysfunction of CFTR causes the genetic disease cystic fibrosis. The CFTR is composed of five domains: two membrane-spanning domains (MSDs), two nucleotide-binding domains (NBDs), and a regulatory (R) domain. Here we review the structure and function of this unique channel, with a focus on how the various domains contribute to channel function. The MSDs form the channel pore, phosphorylation of the R domain determines channel activity, and ATP hydrolysis by the NBDs controls channel gating. Current knowledge of CFTR structure and function may help us understand better its mechanism of action, its role in electrolyte transport, its dysfunction in cystic fibrosis, and its relationship to other ABC transporters.

scholarly journals Cysteine-Free Proteins in the Immunobiology of Arthropod-Borne Diseases

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
J. Santiago Mejia ◽  
Erik N. Arthun ◽  
Richard G. Titus
Keyword(s):  
Plasmodium Falciparum ◽  
Amino Acid ◽  
Distribution Patterns ◽  
Structural Features ◽  
Structure And Function ◽  
Cysteine Residues ◽  
Distribution Analysis ◽  
And Function ◽  
Abundance And Distribution ◽  
Host Parasite

One approach to identify epitopes that could be used in the design of vaccines to control several arthropod-borne diseases simultaneously is to look for common structural features in the secretome of the pathogens that cause them. Using a novel bioinformatics technique, cysteine-abundance and distribution analysis, we found that many different proteins secreted by several arthropod-borne pathogens, includingPlasmodium falciparum, Borrelia burgdorferi, and eight species of Proteobacteria, are devoid of cysteine residues. The identification of three cysteine-abundance and distribution patterns in several families of proteins secreted by pathogenic and nonpathogenic Proteobacteria, and not found when the amino acid analyzed was tryptophan, provides evidence of forces restricting the content of cysteine residues in microbial proteins during evolution. We discuss these findings in the context of protein structure and function, antigenicity and immunogenicity, and host-parasite relationships.

scholarly journals Monoclonal antibodies against chicken type IV and V collagens: electron microscopic mapping of the epitopes after rotary shadowing.

1984 ◽  
Vol 98 (5) ◽  
pp. 1637-1644 ◽  
Author(s):  
R Mayne ◽  
H Wiedemann ◽  
M H Irwin ◽  
R D Sanderson ◽  
J M Fitch ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cleavage Site ◽  
Type Iv Collagen ◽  
Collagen Molecule ◽  
Electron Microscopic ◽  
Type V Collagen ◽  
Type Iv ◽  
Type V ◽  
Rotary Shadowing

The location of the epitopes for monoclonal antibodies against chicken type IV and type V collagens were directly determined in the electron microscope after rotary shadowing of antibody/collagen mixtures. Three monoclonal antibodies against type IV collagen were examined, each one of which was previously demonstrated to be specific for only one of the three pepsin-resistant fragments of the molecule. The three native fragments were designated (F1)2F2, F3, and 7S, and the antibodies that specifically recognize each fragment were called, respectively, IA8 , IIB12 , and ID2 . By electron microscopy, monoclonal antibody IA8 recognized an epitope located in the center of fragment (F1)2F2 and in tetramers of type IV collagen at a distance of 288 nm from the 7S domain, the region of overlap of four type IV molecules. Monoclonal antibody IIB12 , in contrast, recognized an epitope located only 73 nm from the 7S domain. This result therefore provides direct visual evidence that the F3 fragment is located closest to the 7S domain and the order of the fragments must be 7S-F3-(F1)2F2. The epitope for antibody ID2 was located in the overlap region of the 7S domain, and often several antibody molecules were observed to binding to a single 7S domain. The high frequency with which antibody molecules were observed to bind to fragments of type IV collagen suggests that there is a single population of type IV molecules of chain organization [alpha 1(IV)]2 alpha 2(IV), and that four identical molecules must form a tetramer that is joined in an antiparallel manner at the 7S domain. The monoclonal antibodies against type V collagen, called AB12 and DH2 , were both found to recognize epitopes close to one another, the epitopes being located 45-48 nm from one end of the type V collagen molecule. The significance of this result still remains uncertain, but suggests that this site is probably highly immunoreactive. It may also be related to the specific cleavage site of type V collagen by selected metalloproteinases and by alpha-thrombin. This cleavage site is also known to be located close to one end of the type V molecule.

Type IV Collagen Immunostaining Is a Simple, Reliable Diagnostic Tool for Distinguishing Between Adenomatous and Normal Pituitary Glands

2007 ◽  
Vol 131 (6) ◽  
pp. 931-935 ◽  
Author(s):  
Jason Jarzembowski ◽  
Ricardo Lloyd ◽  
Paul McKeever
Keyword(s):  
Pituitary Adenomas ◽  
Type Iv Collagen ◽  
Basement Membranes ◽  
Immunohistochemical Detection ◽  
Secondary Effects ◽  
Hormone Production ◽  
Clonal Population ◽  
Normal Gland ◽  
Type Iv ◽  
Pituitary Glands

Abstract Context.—Pituitary adenomas are clinically diagnosed based on radiologic studies and/or secondary effects of hormone production. Definitive pathologic identification relies on immunohistochemical detection of a clonal population of hormone-producing cells. However, not all adenomas secrete hormones, so performing a battery of stains is inefficient. Reports have shown decreased type IV collagen in the stroma of other epithelial tumors. Objective.—To validate type IV collagen immunohistochemistry as a diagnostic method. Design.—We immunostained 27 adenomas and 19 normal pituitaries. The areas with the sparsest type IV collagen fibers were viewed at 3 magnifications (×10, ×20, and ×40 objectives), counting 1, 3, or 10 microscopic fields. A field was scored as “traversable” if a path existed from any point on the periphery of the field to a point on the approximately opposite periphery that did not cross any stained fibers. Results were compared with reticulin staining and to the existing diagnosis previously determined by histology, hormone immunostaining, and clinical correlation. Results.—Adenomas have less type IV collagen in their basement membranes, leading to sparser, trabecular staining in neoplasms versus a more rigid meshwork pattern in normal glands. One might envision the stained fibers as maze walls—one can traverse medium-powered fields in an adenoma, but one hits dead ends and gets trapped in those of a normal gland. Finding a single representative ×10 field to be traversable was 97.5% sensitive and 96.5% specific for an adenoma. Reticulin staining yielded identical results. Conclusions.—Type IV collagen immunostaining is a simple and reliable method of diagnosing pituitary adenomas.

The relationship between emerging neural crest cells and basement membranes in the trunk of the mouse embryo: a TEM and immunocytochemical study

Development ◽  
1986 ◽  
Vol 98 (1) ◽  
pp. 251-268
Author(s):  
J. Sternberg ◽  
S. J. Kimber
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Neural Crest Cell ◽  
Basement Membranes ◽  
Type Iv ◽  
Transmission Electron ◽  
The Relationship ◽  
Crest Cell

The earliest stage of neural crest cell (NCC) migration is characterized by an epitheliomesenchymal transformation, as the cells leave the neural tube. There is evidence that in a number of cell systems this transformation is accompanied by alteration or depletion of associated basement membranes. This study examines the ultrastructural relationship between mouse NCCs and adjacent basement membranes during the earliest stages of migration from the neural tube. Basement membranes were identified by transmission electron microscopy (TEM) and immunofluorescence using antibodies to type-IV collagen. The ultrastructural features of NCCs and their relationship with surrounding tissues were also examined using TEM. In the dorsal region of the neural tube, from which NCCs originate, the basement membrane was depleted or absent, and with the immunofluorescence technique it was shown that this pattern was reflected in a deficit of type-IV collagen. TEM observations indicated that ultrastructurally NCCs differ from their neuroepithelial neighbours only in overall cell shape and their relationship to other cells and the extracellular matrix.

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