Molecular Analysis of Laminin N-terminal Domains Mediating Self-interactions
| Autor: | Mats Paulsson, Barbara Merkl, Sebastian Haehn, Patrick Tunggal, Christian Frie, Uwe Odenthal, Neil Smyth, Dietmar Schomburg |
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| Rok vydání: | 2004 |
| Předmět: |
Gene isoform
Glycosylation Time Factors Protein family Plasma protein binding Kidney Transfection Biochemistry Basement Membrane Cell Line Receptors Laminin Mice chemistry.chemical_compound Protein structure Laminin Heterotrimeric G protein Cell Adhesion Animals Humans Protein Isoforms Molecular Biology Edetic Acid Chelating Agents Ions biology Circular Dichroism Kidney metabolism Cell Differentiation Cell Biology Surface Plasmon Resonance Recombinant Proteins Extracellular Matrix Protein Structure Tertiary Kinetics Cross-Linking Reagents chemistry Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization Calibration Biophysics biology.protein Calcium Electrophoresis Polyacrylamide Gel Dimerization Plasmids Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 279:44504-44512 |
| ISSN: | 0021-9258 |
| Popis: | The ability of laminins to self-polymerize is crucial for the formation of basement membranes. Development of this polymerized network has profound effects upon tissue architecture as well as on the intracellular organization and differentiation of neighboring cells. The laminin N-terminal (LN) domains have been shown to mediate this interaction and studies using proteolytic fragments derived from laminin-1 led to the theory that network assembly depends on the formation of a heterotrimeric complex between LN domains derived from alpha, beta, and gamma chains in different laminin molecules with homologous interactions being insignificant. The laminin family consists of 15 known isoforms formed from five alpha, three beta, and three gamma chains, of which some are truncated and lack the N-terminal LN domain. To address whether the model of heterotrimeric complex formation is applicable to laminin isoforms other than laminin-1, eight LN domains found in the laminin protein family were recombinantly expressed and tested in three different assays for homologous and heterologous interactions. The results showed that the lack of homologous interactions is an exception, with such interactions being seen for LN domains derived from all alpha chains and from the beta2 and beta3 subunits. The gamma chain-derived LN domains showed a far more limited binding repertoire, particularly in the case of the gamma3 chain, which is found present in a range of non-basement membrane locations. Further, whereas the interactions depended upon Ca2+ ions, with EDTA reversibly abrogating binding, EDTA-induced conformational changes were not reversible. Together these results demonstrate that the assembly model proposed on the basis of laminin-1 may be a simplification, with the assembly of naturally occurring laminin networks being far more complex and highly dependent upon which laminin isoforms are present. |
| Databáze: | OpenAIRE |
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