Involvement of the YIGSR sequence of laminin in protein tyrosine phosphorylation.

We have examined the mechanism of signaling by the 67 kDa YIGSR binding protein of laminin and its properties in neuroblastoma cells. Ligand displacement analysis showed that the interaction with the C(YIGSR)3-NH2 peptide amide is of intermediate affinity (1.5 x 10[-7] M). Cross-linking experiments with sulfo-MBS detected an additional protein with a molecular mass of 116 kDa that binds the YIGSR sequence. Incubation of neuroblastoma cells with C(YIGSR)3-NH2 peptide amide or antibody directed against the 67 kDa laminin binding protein induces tyrosine phosphorylation of proteins with a molecular mass ranging from 115 to 130 kDa and another heterogeneous protein group of 32 kDa.