Protein interactions and subcellular localization in S-RNase-based self-incompatibility.

The recent identification of several proteins playing key roles in S-RNase-based gametophytic self-incompatibility has led both to a greater understanding of the molecular biology of this response, as well as to questions regarding the precise mechanism by which compatible pollen tubes are recognized and accepted. A proposed variant SCF(SLF) (where SCF is SSK1/cullin/F-box and SLF is S-locus F-box) ubiquitin ligase complex is thought to play a central role in recognizing and inhibiting non-self S-RNases, but the exact role of ubiquitination remains unclear. How the possible sequestration of non-self S-RNases in a pollen vacuolar compartment can be reconciled with the need for protein interaction between S-RNase and the SCF(SLF) complex needs to be determined. Current work to answer these questions focuses on more precisely defining quantitative protein interactions and subcellular localization of proteins involved in S-RNase-based gametophytic self-incompatibility.