Basal lamina laminin

Extracellular Basal lamina, Laminin, elastin, Unknown Immune-... 

After type IV collagen, laminin is the most abundant protein in basal laminae. Laminin provides additional structural support for the tissues through its ability to bind to type IV collagen, to other molecules present in the ECM, and to cell surface-associated proteins (the integrins, see section D). 

LAMININ IS A MAJOR PROTEIN COMPONENT OF RENAL GLOMERULAR OTHER BASAL LAMINAS... 

Basal laminas are specialized areas of the ECM that surround epithelial and some other cells (eg, muscle cells) here we discuss only the laminas found in the renal glomerulus. In that strucmre, the basal lamina is contributed by two separate sheets of cells (one endothelial and one epithelial), each disposed on opposite sides of the lamina these three layers make up the glomerular membrane. The primary components of the basal lamina are three proteins—laminin, entactin, and type IV collagen—and the GAG heparin or heparan sulfate. These components are synthesized by the underlying cells. 

While one end of the dystrophin molecule binds to actin filaments, the C-terminal domain associates with several additional proteins to form a dystrophin-glycoprotein complex (see figure)/1 k Dystrophin is linked directly to the membrane-spanning protein P-dystroglycan, which in the outer membrane surfaces associates with a glycoprotein a-dystroglycan. The latter binds to laminin-2 (Fig. 8-33), a protein that binds the cell to the basal lamina. Four... 

Fig. 3.2 Relationship of the connective tissue stroma to an epithelium. Fibroblasts secrete unique types of laminin proteins that interact with each other and type IV collagen, to form a basal lamina (yellow) that is tightly attached to the connective tissue (stromal) cells and also to the associated muscle or epithelial cell. The kidney glomerulus is a specialized tissue in which the stroma is absent and endothelial cells and epithelial cells are separated by the basal lamina which filters the blood as the first step in urine collection. The attachment of an epithelium to stromal collagen is discussed in detail in Chap. 5 (Fig. 19-55 in The Molecular Biology of the Cell. B. Alberts et al., 4th Ed. 2002. Garland Science, Taylor Francis Group, NY)...

FIGURE 6-13 Major components of the basal lamina. Schematic model of basal lamina showing the organization of the major protein components. Type IV collagen and laminin each form two-dimensional networks, which are cross-linked by entactin and perlecan molecules. [Adapted from B. Alberts et al., 1994, Molecular Biology of the Cell, 3d ed., Garland, p. 991.1... 

Laminin, a Multiadhesive Matrix Protein, Helps Cross-link Components of the Basal Lamina... 

A FIGURE 6-16 Laminin, a heterotrimeric multiadhesive matrix protein found in all basal laminae, (a) Schematic model showing the general shape, location of globular domains, and coiled-coil region in which laminin s three chains are covalently linked by several disulfide bonds. Different regions of laminin bind to cell-surface receptors and various matrix components. 

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