Laminin variants: Why, where and when?

Engvall, Eva

doi:10.1038/ki.1993.2

Cited by 122 publications

(65 citation statements)

References 45 publications

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“…Thus, changes in the accumulation and localization of laminin and the laminin a1 and p l subunit chains at or near the time of differentiation of alveolar type I and type I1 epithelial cells in fetal lung tissue are suggestive that laminin may play an important role in mediating cellular differentiation of these cell types during rabbit fetal lung development. Based on our immunolocalization data concerning the laminin a1 and p l subunit chains and the fact that laminin exists as a trimeric molecule in most tissues (Engvall, 1993), it is apparent that other laminin subunit chains must also be expressed in developing lung tissue in vivo. In the future, it will be important to identify other laminin subunit chains that are expressed during fetal lung development and correlate their expression with key developmental events such as alveolar epithelial differentiation.…”

Section: Discussionmentioning

confidence: 93%

Characterization of α1, β1, and γ1 laminin subunits during rabbit fetal lung development

Durham

Snyder

1995

Developmental Dynamics

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Laminin-1 is an extracellular matrix protein composed of three polypeptide chains that are designated al, pl, and yl. We investigated the expression of laminin cwl, pl, and y l subunit chains during several stages of rabbit fetal lung development. Utilizing polyclonal antibodies directed against human placental laminin and immunoblot analysis, we found that the highest levels of laminin al, pl, and y l subunit chains in the fetal lung were present on day 26 of gestation (term = 31 days), coincident with the initiation of alveolar epithelial cell differentiation. Levels of the laminin chains were approximately five times higher in fetal lung at day 26 of gestation than in adult lung tissue. Different temporal patterns of laminin al, pl, and y l subunit chain expression were observed, data suggestive that the chains are independently regulated during lung development. Laminin was localized to the basement membranes of bronchi, bronchioles, prealveolar ducts, and blood vessels in fetal lung tissue, as shown by immunostaining with polyclonal laminin antibodies. A similar staining pattern was observed in adult lung tissue, but the alveolar wall was also stained. Laminin was also observed surrounding a few mesenchymal cells in fetal lung on day 19 of gestation; the number of positive mesenchymal cells increased with lung development. Laminin a1 subunit chains, detected using a monoclonal antibody, were present in the basement membranes of bronchi, bronchioles, prealveolar ducts, and blood vessels in fetal lung tissue. No laminin a1 chain staining was observed in the mesenchyme of early fetal lung tissue. Using a monoclonal antibody, laminin P l subunit chains were immunolocalized in the basement membranes of bronchi, bronchioles, in prealveolar ducts, and surrounding some mesenchymal cells in fetal lung tissue. Laminin a1 and p l subunit chains in adult lung tissue were present in basement membranes of airways, blood vessels, and alveoli. Thus, changes in the localization and accumulation of laminin near the time of alveolar type I and type I1 epithelial cell differentiation suggest that laminin may play a role in mediating the differentiation of these cell types during rabbit fetal lung development.

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Section: Discussionmentioning

confidence: 93%

Characterization of α1, β1, and γ1 laminin subunits during rabbit fetal lung development

Durham

Snyder

1995

Developmental Dynamics

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“…The B chains may be detected at the two-cell stage (5,16), whereas the A chain is detected from the 16-cell stage (5). There are variant forms oflaminin within a given species which are expressed at different stages of development and in different tissue locations (4,18). In human skin the so-called "classic" laminin, composed of three subunits, A, Bland B2 chains, is the predominant isoform in the cutaneous basement membrane zone (19)(20).…”

Section: Discussionmentioning

confidence: 99%

Expression of the High-Affinity Laminin Receptor (67 kDa) in Normal Human Skin and Appendages

Cavalieri

Rotoli

Feliciani

et al. 2005

Int J Immunopathol Pharmacol

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The interaction of cells with extracellular matrix components plays a significant role in the regulation of cell biology. Laminin is a large glycoprotein involved in fundamental interactions between cells and the basement membrane. Several cell surface receptors are responsible for cell-matrix interactions. The 67 kDa high affinity laminin receptor, 67LR, is involved in the adhesion of normal cells to the laminin network and is also associated with the metastatic phenotype of some tumoral cells. We have investigated the expression of laminin and of the 67LR in normal human skin using immunoperoxidase staining. Twenty samples of skin were analyzed. Antibody against laminin reacted in a continuous linear band at the dermal-epidermal junction, as well as basement membranes of hair follicles, sebaceous and eccrine sweat glands, and dermal blood vessels. The epidermis and the follicular epithelium were negative for laminin. The 67LR seemed not to be expressed on the basal surface of basal keratinocytes. The major expression of this receptor may be detected in the upper half of the spinous layer and in the granular layer. The cells of the outer root sheath in hair follicle showed the same immunohistochemical pattern described for epidermis. In sebaceous glands and in eccrine sweat glands the secreting epithelium was positive. Endothelial cells of dermal blood vessels were routinely positive for 67LR. We observed that the expression of the 67LR in normal human skin is mostly located in epidermal areas in which the keratinizing process was particularly advanced.The interaction of cells with extracellular matrix components plays a significant role in the regulation of cell morphology, growth and differentiation and contributes to the pathogenesis of cancer (1). Extracellular matrix organization is particularly complex at the interface between histologically dissimilar tissues that originate from different primary germ layers. In this area the so-called basement membrane is formed (2).The skin basement membrane zone is among the most complex basement membranes of the human body (3). Several macromolecules have been identified within the basement membrane zone. Among these laminin is a ubiquitous, large glycoprotein with a molecular weight of approximately 900 kDa. It is composed of three genetically different subunits, named A, B I and B2 in the classical form, which assemble into a cruciform structure with one long arm and three short arms (4-5).Laminin is thought to form a major basement membrane network located in the lamina lucida (6) and to be involved in important interactions between cells and basement membrane (7). Epidermal cells and extracellular matrix proteins interact through specific receptors of the cellular surface. To date, severallaminin binding proteins have been identified (8). The high affinity laminin receptor, molecular weight 67 kDa, was the first laminin receptor to be identified in 1983 (9-11).This receptor is physiologically expressed by a large variety of cells and seems to be involved in the a...

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“…In light of this complexity, a new nomenclature has been adopted where the designated A, B1 and B2 chains have been replaced by alpha, beta and gamma respectively, and the identification of forms is distinguished by arabic numbers (75). Functionally, laminins have been shown to mediate several cellular activities, namely the promotion of adhesion, growth, polarization and differentiation depending on the cell type studied (10, 76,77). Variability in spatial and temporal expression for a number of these laminin chains (78,79) suggests that different heterotrimeric forms of laminin could perform distinct functions.…”

Section: Basement Membrane Compositionmentioning

confidence: 99%

Integrins and human intestinal cell functions

Beaulieu¹

1999

Front Biosci

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Laminin variants: Why, where and when?

Cited by 122 publications

References 45 publications

Characterization of α1, β1, and γ1 laminin subunits during rabbit fetal lung development

Characterization of α1, β1, and γ1 laminin subunits during rabbit fetal lung development

Expression of the High-Affinity Laminin Receptor (67 kDa) in Normal Human Skin and Appendages

Integrins and human intestinal cell functions

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