Abstract
In Brassica self-incompatibility (SI), the recognition of self/nonself pollen grains is controlled by the S-locus, which encodes at least two highly polymorphic proteins: S-locus receptor kinase (SRK) and S-locus protein 11 (SP11). We have previously shown that SP11, which is located in the pollen coat, directly binds to its cognate SRK, located on the plasma membrane of stigma cells, with high affinity and induces its autophosphorylation. We have also shown found that MLPK, a membrane-anchored cytoplasmic kinase, is involved in SI signal transduction. Recent biochemical and molecular biological studies suggested that plasma membrane localization of SRK is essential for the SP11 high-affinity binding. The membrane localization of MLPK is also suggested to be essential for SI signal transduction. The implications of these findings will be discussed.
