Laminin isolation

Loke, Y W., Gardner, L, and Grabowska, A. (1989) Isolation of extravillous trophoblast cells by attachment to laminin-coated magnetic beads. Placenta 10, 407-415... 

The cells from the third category, such as epithelial cells isolated from mammal glands, testes, ovaries, pituitary gland, prostate, and from ocular tissue, generally proliferate with more difficulty in a defined medium. Besides maintenance factors, these cells may also need proteins from the ECM to promote their adhesion. Those proteins can be collagen, fibronec-tin, or laminin. Non-peptide factors, such as retinol (50 ng/ml) and corticosteroids (10-100 ng/ml), may also be necessary. 

Advances in isolating and identifying cDNA clones for laminin provided considerable additional information on the amino acid sequences at the carboxyl end of the B1 and B2 chains (Barlow et al., 1984). These analyses showed that at least 350 residues of the B1 chain and over 200 residues of the B2 chain had the a-helical heptad repeat and predicted that these chains would be aligned together, along the long arm of laminin in a coiled-coil a-helical structure. 

Rao CN, Bardcy SH, Tetranova VP, Liotta LA Isolation of a tumor cell laminin receptOT. Biodiem Biq>hys Res Commun 111 804-808,1983. 

The naturally occurring PP2A inhibitor cytostatin (152), which was isolated from a Streptomyces inhibits the adhesion of B16 melanoma cells to laminin and collagen, displays anti metastatic and cytotoxic activity and induces apoptosis of B16 melanoma cells. The synthesis of the 4S,5S,6S,10S,11S,12S isomer of cyto-... 

Lesot, H., Kiihl, U. and von der Mark, K. (1983). Isolation of a laminin binding protein from muscle cell membranes. EMBOJ. 2, 861-865. 

Malinoff, H.L., and Wicha, M.S. (1983). Isolation of a cell surface receptor for laminin from murine fibrosarcoma cells./ Cell. Biol. 96, 1475-1479. 

Laminin (LN), another adhesive glycoprotein, is usually isolated from the mouse EHS-sarcoma, where it consists of an A-chain (about 400 kDa) and B1 and B2 chains (each about 200 kDa) linked to form a cruciform molecule. Another molecule, entactin, is non-covalently linked to LN. This tumor LN configuration is not the only one possible and LN in different tissues and stages of development may show deletions of chains or other alterations (Cooper and MacQueen, 1983). 

Other putative laminin-binding proteins have been described from a number of sources (for example, Smalheiser and Schwartz, 1987). Kleinman et al. (1991) used a synthetic peptide derived from the a chain of laminin to elute a 110 kDa protein from brain tissue however, the resulting molecule had sequence similarity to nucleolin. This putative receptor appears to be expressed in postnatal brain, particularly the hippocampus (Luckinbilledds et al., 1995). Albini et al. (1992) have described the isolation of a similar 100 kDa molecule from Y-79 retinoblastoma cells that is eluted from laminin affinity columns by 20 mM EDTA this binding protein has only intermediate affinity for laminin, however, but may act to influence gene expression independent of attachment. Laminin has been reported to bind to Ng-CAM on the basis of antibody inhibition studies, an interaction important for the formation of neuron-glia adhesion (Grumet etal., 1993). 

Douville, P.J., Harvey, W.J. and Carbonetto, S. (1988) Isolation and partial characterization of high affinity laminin receptors in neural cells. J. Biol. Chem. 263 14964—14969. 

Engvall, E., Earwicker, D., Haaparant, T., Ruoslahti, E. and Sanes, J.R. (1990) Distribution and isolation of four laminin variants tissue restricted distribution of heterotrimers assembled from five different subunits. Cell Reg. 1 731-740. 

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