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Updated: Jul 31, 2026

Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
Published on: March 9, 2010
Isolation and activity of proteolytic fragment of laminin-5 alpha3 chain
Y Tsubota1, H Mizushima, T Hirosaki
1Division of Cell Biology, Graduate School of Integrated Sciences, Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, 244-0813, Japan.
Abstract:
Laminin-5 (alpha3beta3gamma2) is an important component of epithelial basement membranes. The 190-kDa alpha3 chain undergoes extracellular cleavage within the carboxyl (C) terminus consisting of five globular domains (G1 to G5), producing the mature laminin-5 with the 160-kDa alpha3 chain. To understand the physiological meaning of this processing, we isolated the C-terminal fragments of the alpha3 chain from the conditioned media of two kinds of human cell lines. The amino-terminal sequence of the fragments suggested that the cleavage occurs at Gln(1337)-Asp(1338) in the spacer region between the G3 and G4 domains. The G4-G5 fragment itself did not show significant activity, but it stimulated cell migration in the presence of a low concentration of the mature laminin-5, suggesting its regulatory role in cell migration.
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