Biologically Active Sequences in the Mouse Laminin α3 Chain G Domain

The laminin α3 chain is mainly expressed at the skin, and its C-terminal G domain has a critical role in multiple biological functions. We screened for biologically active sites on the mouse laminin α3 chain G domain using 107 synthetic peptides on coated plates and conjugated to Sepharose beads with HT1080 human fibrosarcoma cells, HaCaT human skin keratinocyte cells, and human dermal fibroblasts (HDFs). Eleven peptides exhibited cell attachment activity with respect to the peptide-coated plates and/or peptide−Sepharose beads. MA3G28 (WTIQTTVDRGLL) strongly binds to HaCaT cells. Four peptides promoted PC12 cell neurite outgrowth. Heparin inhibited attachment of HDFs to eight peptides on the coated plates. In contrast, EDTA significantly inhibited attachment of HDFs to MA3G27 (NAPFPKLSWTIQ) and MA3G28 but had no effect on the attachment of the other peptides. HDF cells formed well-organized actin stress fibers and focal contacts with vinculin accumulation on MA3G27. Additionally, attachment of HDFs to MA3...