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Laminin Structure
Published by Anonymous on 2007/9/24 (2356 reads)
1: Matrix Biol. 2000 Aug;19(4):309-17.


Structure and function of laminin LG modules.

Timpl R, Tisi D, Talts JF, Andac Z, Sasaki T, Hohenester E.

Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, D-82152, Martinsried, Germany. timpl@biochem.mpg.de

Laminin G domain-like (LG) modules of approximately 180-200 residues are found in a number of extracellular and receptor proteins and often are present in tandem arrays. LG modules are implicated in interactions with cellular receptors (integrins, alpha-dystroglycan), sulfated carbohydrates and other extracellular ligands. The recently determined crystal structures of LG modules of the laminin alpha2 chain reveal a compact beta sandwich fold and identify a novel calcium binding site. Binding epitopes for heparin, sulfatides and alpha-dystroglycan have been mapped by site-directed mutagenesis and show considerable overlap. The epitopes are located in surface loops around the calcium site, which in other proteins (agrin, neurexins) are modified by alternative splicing. Efficient ligand binding often requires LG modules to be present in tandem. The close proximity of the N- and C-termini in the LG module, as well as a unique link region between laminin LG3 and LG4, impose certain constraints on the arrangement of LG tandems. Further modifications may be introduced by proteolytic processing of laminin G domains, which is known to occur in the alpha2, alpha3 and alpha4 chains.

Publication Types:
Research Support, Non-U.S. Gov't
Review

PMID: 10963991 [PubMed - indexed for MEDLINE]

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2: Methods Mol Biol. 2000;139:27-37.


Analysis of laminin structure and function with recombinant glycoprotein expressed in insect cells.

Mathus TL, Yurchenco PD.

Robert Wood Johnson Medical School, Piscataway, NJ, USA.

Publication Types:
Review

PMID: 10840775 [PubMed - indexed for MEDLINE]

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3: Pathobiology. 1999 Mar-Apr;67(2):84-91.


Role of laminin isoforms in glomerular structure.

Hansen K, Abrass CK.

Division of Nephrology and Department of Medicine, VA Puget Sound Health Care System, Seattle, Wash. 98108, USA.

Laminin along with collagen type IV, proteoglycans, and entactin are major components of basement membranes. Basement membrane components are synthesized at high levels during development. The formation of specialized basement membranes may play important roles in cell and tissue function by influencing cell proliferation, phenotype, migration and gene expression as well as tissue architecture. The growing diversity of laminin isoforms influences the formation of distinct basement membranes. Many of the laminin chains sequenced to date are expressed during glomerular development under strict temporal control. Also, some studies suggest that additional laminin chains exist and contribute to unique isoforms expressed within the renal glomerulus. This article will review the status of characterization of laminin isoforms expressed by glomerular cells, point out possible differences in isoforms expressed by different species, and discuss the implications of the complexity of glomerular laminins. In order to fully understand the nature of the glomerular laminins and their importance, information from studies of cells in culture, whole tissue, and those that use molecular and protein analysis must be integrated.

Publication Types:
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Review

PMID: 10023136 [PubMed - indexed for MEDLINE]

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4: Virchows Arch. 1996 Dec;429(6):311-22.


Molecular variants of fibronectin and laminin: structure, physiological occurrence and histopathological aspects.

Kosmehl H, Berndt A, Katenkamp D.

Institute of Pathology, Friedrich Schiller University, Jena, Germany.

This review deals with biological and pathological aspects of various isoforms of the matrix molecules fibronectin and laminin. They are generated by different molecular mechanisms: ED-A+ and ED-B+ fibronectin by alternative splicing of pre mRNA, de novo-glycosylated fibronectin by alternative post-translational O-linked glycosylation of the IIICS region, and the laminin isoforms by exchange of single chains of the heterotrimeric molecule. In contrast to the "common" fibronectin, the distribution of ED-B+ and de novo-glycosylated fibronectin is restricted to embryonic tissues; they subsequently reappear in granulation tissue, in fibrosing processes and in tumour stroma. The expression of these so-called oncofetal fibronectins is stimulated by growth factors (TGF beta). The association of the ED-B+ fibronectin with proliferative activity and newly formed vessels identifies this fibronectin variant as a marker of cellular activity in the process of fibrosis and as a suitable agent for the evaluation of tumour angioneogenesis. Initial results suggest a correlation between the amount of ED-B+ and de novo-glycosylated fibronectin in tumour stroma and the behaviour of carcinomas with regard to their invasiveness and propensity for metastatic dissemination. The current nomenclature of the laminin molecule family is presented. The laminin chain constitution of basement membranes switches from embryonic or proliferatively active to adult terminally differentiated tissues [disappearance of the laminin beta 2 (s) chain] and depends on the tissue type. The discrepancy between the loss of basement membranes (multiple basement membrane defects) in carcinomas and the recently reported increased laminin chain synthesis in these tumours may be explained by abundant laminin chain deposition outside the basement membrane in the carcinoma invasion front, possibly associated with enhanced adhesion of budding tumour cells.

Publication Types:
Research Support, Non-U.S. Gov't
Review

PMID: 8982375 [PubMed - indexed for MEDLINE]

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5: FASEB J. 1990 Feb 1;4(2):148-60.


Structure and function of laminin: anatomy of a multidomain glycoprotein.

Beck K, Hunter I, Engel J.

Institute for Biophysics, University Linz, Austria.

Laminin is a large (900 kDa) mosaic protein composed of many distinct domains with different structures and functions. Globular and rodlike domains are arranged in an extended four-armed, cruciform shape that is well suited for mediating between distant sites on cells and other components of the extracellular matrix. The alpha-helical coiled-coil domain of the long arm is involved in the specific assembly of the three chains (A, B1, B2, and possible variants) of laminin and is the only domain composed of multiple chains. It is terminated by a large globular domain composed of five homologous subdomains formed by the COOH-terminal part of the A chain. Sites for receptor-mediated cell attachment and promotion of neurite outgrowth reside in the terminal region of the long arm. A second cell attachment site, a cell signaling site with mitogenic action, binding sites for the closely associated glycoprotein nidogen/entactin, and regions involved in calcium-dependent aggregation are localized in the short arms. These domains, which to a large extent are composed of Cys-rich repeats with limited homology to EGF, are the most highly conserved regions in laminins of different origin. At present, most structural and functional data have been collected for a laminin expressed by a mouse tumor, which can be readily isolated in native form and dissected into functional fragments by limited proteolysis. Increasing information on laminins from different species and tissues demonstrates considerable variations of structure. Isoforms of laminin assembled from different chains are focally and transiently expressed and may serve distinct functions at early stages of development even before being laid down as major components of basement membranes.

Publication Types:
Research Support, Non-U.S. Gov't
Review

PMID: 2404817 [PubMed - indexed for MEDLINE]

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6: Curr Opin Cell Biol. 1989 Oct;1(5):964-7.


Laminin: structure, functions and receptors.

Kleinman HK, Weeks BS.

Laboratory of Developmental Biology and Anomalies, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland.

Publication Types:
Review

PMID: 2534046 [PubMed - indexed for MEDLINE]

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7: Tanpakushitsu Kakusan Koso. 1987 May;32(5):397-410.


[Laminin B1 chain; its structure and gene expression]

[Article in Japanese]

Kohno K, Sasaki M, Kato S, Yamada Y.

Publication Types:
Review

PMID: 3303142 [PubMed - indexed for MEDLINE]

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8: Pathol Biol (Paris). 1986 Oct;34(8):955-63.


[Laminin: biosynthesis, structure and functions]

[Article in French]

Lissitzky JC, Kopp F, Charpin C, Chiarotti Y, Bignon C, Martin PM.

Biosynthesized by epithelial, endodermal and Swann type cells, laminin (Lam) is a cross shaped multifunctional glycoprotein formed by the multimeric assembly of subunits which result from the activation of several genes. In vivo, depending on its location, because of its adhesive properties and multivalent affinities, Lam is in association as a part of supramolecular complexes together with compounds of the plasma, the basement membrane and the cell coat. In the basement membrane (MB) Lam has structural and functional roles. It may also be adsorbed on the cell coat or secreted. It is interacting with epithelial cells by the way of a plasma membrane receptor and has a role to play in cellular differentiation and proliferation. Lam is a molecular link of epithelial cells to MB. These features implicate the molecule in organogenesis, embryogenesis and post-traumatic healing. As a structural component of MB and as an attachment factor, Lam is involved: 1 in tumoral invasion which allows metastatic spreading, 2 in homing because metastatic cell display an increased receptivity to the molecule. The study of Lam expression, Lam receptivity and their factors of control should lead to a better understanding of the biochemical and molecular basis of differentiation, embryogenesis, organogenesis and metastasis.

Publication Types:
English Abstract
Research Support, Non-U.S. Gov't
Review

PMID: 3537941 [PubMed - indexed for MEDLINE]
 

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