Laminins, a family of extracellular matrix glycoproteins, are the major noncollagenous constituent of basement membranes. They have been implicated in a wide variety of biological processes including cell adhesion, differentiation, migration, signaling, neurite outgrowth and metastasis. Laminins are composed of 3 non identical chains: laminin alpha, beta and gamma (formerly A, B1, and B2, respectively) and they form a cruciform structure consisting of 3 short arms, each formed by a different chain, and a long arm composed of all 3 chains. Each laminin chain is a multidomain protein encoded by a distinct gene. Several isoforms of each chain have been described. Different alpha, beta and gamma chain isomers combine to give rise to different heterotrimeric laminin isoforms, which are designated by Arabic numerals in the order of their discovery, i.e. alpha1beta1gamma1 heterotrimer is laminin 1. The biological functions of the different chains and trimer molecules are largely unknown, but some of the chains have been shown to differ with respect to their tissue distribution, presumably reflecting diverse functions in vivo. This gene encodes the beta chain isoform laminin, beta 1. The beta 1 chain has 7 structurally distinct domains, which it shares with other beta chain isomers. The C-terminal helical region containing domains I and II are separated by domain alpha, domains III and V contain several EGF-like repeats, and domains IV and VI have a globular conformation. Laminin, beta 1 is expressed in most tissues that produce basement membranes, and is one of the 3 chains constituting laminin 1, the first laminin isolated from Engelbreth-Holm-Swarm (EHS) tumor. A sequence in the beta 1 chain that is involved in cell attachment, chemotaxis, and binding to the laminin receptor was identified and shown to have the capacity to inhibit metastasis.
5′-UTR of Laminin-B1 harbors IRES (internal ribosome entry site) between −293 and −1 upstream of the start codon. IRES are involved in cancer malignancy. [Petz 2011 
^Roche KB, Moore JW, Surana RB, Wilson BE (May 1989). "Aortic root dilatation associated with partial trisomy 7(q31.2----qter)". Pediatr Cardiol10 (1): 53–5. doi:10.1007/BF02328637. PMID2704655.
^Bonneau D, Huret JL, Godeau G, Couet D, Putterman M, Tanzer J, Babin P, Larregue M (Sep 1991). "Recurrent ctb(7)(q31.3) and possible laminin involvement in a neonatal cutis laxa with a Marfan phenotype". Hum Genet87 (3): 317–9. PMID1864606.
Ljubimova JY, Fujita M, Khazenzon NM, et al. (2006). "Changes in laminin isoforms associated with brain tumor invasion and angiogenesis.". Front. Biosci.11 (1): 81–8. doi:10.2741/1781. PMID16146715.
Vuolteenaho R, Chow LT, Tryggvason K (1990). "Structure of the human laminin B1 chain gene.". J. Biol. Chem.265 (26): 15611–6. PMID1975589.
Sasaki M, Kato S, Kohno K, et al. (1987). "Sequence of the cDNA encoding the laminin B1 chain reveals a multidomain protein containing cysteine-rich repeats.". Proc. Natl. Acad. Sci. U.S.A.84 (4): 935–9. doi:10.1073/pnas.84.4.935. PMC304334. PMID3493487.
Pikkarainen T, Eddy R, Fukushima Y, et al. (1987). "Human laminin B1 chain. A multidomain protein with gene (LAMB1) locus in the q22 region of chromosome 7.". J. Biol. Chem.262 (22): 10454–62. PMID3611077.
Jaye M, Modi WS, Ricca GA, et al. (1987). "Isolation of a cDNA clone for the human laminin-B1 chain and its gene localization.". Am. J. Hum. Genet.41 (4): 605–15. PMC1684322. PMID3661559.
Lohi J, Leivo I, Franssila K, Virtanen I (1997). "Changes in the distribution of integrins and their basement membrane ligands during development of human thyroid follicular epithelium.". Histochem. J.29 (4): 337–45. doi:10.1023/A:1026482700109. PMID9184849.
Taylor J, Muntoni F, Robb S, et al. (1997). "Early onset autosomal dominant myopathy with rigidity of the spine: a possible role for laminin beta 1?". Neuromuscul. Disord.7 (4): 211–6. doi:10.1016/S0960-8966(97)00461-6. PMID9196901.
Sewry CA, D'Alessandro M, Wilson LA, et al. (1997). "Expression of laminin chains in skin in merosin-deficient congenital muscular dystrophy.". Neuropediatrics28 (4): 217–22. doi:10.1055/s-2007-973703. PMID9309712.
Mahida YR, Beltinger J, Makh S, et al. (1998). "Adult human colonic subepithelial myofibroblasts express extracellular matrix proteins and cyclooxygenase-1 and -2.". Am. J. Physiol.273 (6 Pt 1): G1341–8. PMID9435560.
O'Grady P, Thai TC, Saito H (1998). "The laminin-nidogen complex is a ligand for a specific splice isoform of the transmembrane protein tyrosine phosphatase LAR.". J. Cell Biol.141 (7): 1675–84. doi:10.1083/jcb.141.7.1675. PMC2133008. PMID9647658.
Koch M, Olson PF, Albus A, et al. (1999). "Characterization and expression of the laminin gamma3 chain: a novel, non-basement membrane-associated, laminin chain.". J. Cell Biol.145 (3): 605–18. doi:10.1083/jcb.145.3.605. PMC2185082. PMID10225960.
Kikkawa Y, Sanzen N, Fujiwara H, et al. (2000). "Integrin binding specificity of laminin-10/11: laminin-10/11 are recognized by alpha 3 beta 1, alpha 6 beta 1 and alpha 6 beta 4 integrins.". J. Cell. Sci. 113. ( Pt 5): 869–76. PMID10671376.
Hirosaki T, Mizushima H, Tsubota Y, et al. (2000). "Structural requirement of carboxyl-terminal globular domains of laminin alpha 3 chain for promotion of rapid cell adhesion and migration by laminin-5.". J. Biol. Chem.275 (29): 22495–502. doi:10.1074/jbc.M001326200. PMID10801807.
Champliaud MF, Virtanen I, Tiger CF, et al. (2000). "Posttranslational modifications and beta/gamma chain associations of human laminin alpha1 and laminin alpha5 chains: purification of laminin-3 from placenta.". Exp. Cell Res.259 (2): 326–35. doi:10.1006/excr.2000.4980. PMID10964500.
Pedraza C, Geberhiwot T, Ingerpuu S, et al. (2000). "Monocytic cells synthesize, adhere to, and migrate on laminin-8 (alpha 4 beta 1 gamma 1).". J. Immunol.165 (10): 5831–8. PMID11067943.