title: Characterization of laminin 5B and NH2-terminal proteolytic fragment of its alpha3B chain: promotion of cellular adhesion, migration, and proliferation.
abstract: Various laminin isoforms have specific biological functions depending on their structures. Laminin 5A, which consists of the three truncated chains alpha3A, beta3, and gamma2, is known to have strong activity to promote cell adhesion and migration, whereas a laminin 5 variant consisting of a full-sized alpha3 chain (alpha3Beta) and the beta3 and gamma2 chains, laminin 5B, has not been characterized yet. In the present study, we for the first time cloned a full-length human laminin alpha3B cDNA and isolated the human laminin 5B protein. The molecular size of the mature alpha3B chain (335 kDa) was approximately twice as large as the mature alpha3A chain in laminin 5A. Laminin 5B had significantly higher cell adhesion and cell migration activities than laminin 5A. In addition, laminin 5B potently stimulated cell proliferation when added into the culture medium directly. Furthermore, we found that the alpha3B chain undergoes proteolytic cleavage releasing a 190-kDa NH(2)-terminal fragment. The 190-kDa fragment had activities to promote cellular adhesion, migration, and proliferation through its interaction with integrin alpha(3)beta(1). These activities of the NH(2)-terminal structure of the alpha3B chain seem to contribute to the prominent biological activities and the physiological functions of laminin 5B.
authors.affiliation: Division of Cell Biology, Kihara Institute for Biological Research, Yokohama City University, Yokohama 244-0813, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kariya
authors.forename: Chie
authors.initials: C
authors.lastname: Yasuda
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Kumiko
authors.initials: K
authors.lastname: Ishida
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tsubota
authors.forename: Kaoru
authors.initials: K
authors.lastname: Miyazaki
mesh_terms: D002448:Cell Adhesion; D002455:Cell Division; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement; D003001:Cloning, Molecular; D003470:Culture Media; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors; D006801:Humans; D015151:Immunoblotting; D016023:Integrins / Q000737:chemistry; D007797:Laminin / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D013997:Time Factors; D014162:Transfection
chemical_list: D003470:Culture Media; D018076:DNA, Complementary; D016023:Integrins; D007797:Laminin; D020033:Protein Isoforms; D011994:Recombinant Proteins; C095567:laminin alpha 3; D004492:Edetic Acid