RGD-dependent growth of maize calluses and immunodetection of an integrin-like protein.

When maize calluses are grown in the presence of the RGD peptide, important morphological changes are observed indicating the presence of a likely RGD-binding receptor. Polyclonal antibodies generated against the human beta1 integrin subunit, the platelet integrin alphaIIbeta3 (P23) and antibodies specific for either the beta3 platelet chain or the alphaIIb polypeptide cross-react with glycoproteins in Western blot analyses. Immunoprecipitation assays indicate that this maize integrin-like protein shares structural similarities with the animal alphaIIbeta3 complex. We also show that AcAt2, a polyclonal antibody raised against Arabidopsis proteins purified on an RGD column, interacts with a maize protein.