查看文章

The plant-specific Rop family GTPases are versatile molecular switches in many processes during plant growth, development, and responses to the environment. To understand how Rop achieves its functional versatility in signaling, we performed a genome-wide identification of putative Rop targets using a combination of the yeast two-hybrid method, bioinformatic tools, and a robust functional assay in pollen. In this study, we have identified 11 Arabidopsis genes encoding novel proteins, termed RICs (for Rop-interactive CRIB motif–containing proteins), that contain a CRIB (for Cdc42/Rac-interactive binding) motif required for their specific interaction with GTP-bound Rop1. RICs are divergent and classified into five groups that share little sequence homology outside of the conserved Rop-interactive domain. Overexpression in tobacco pollen tubes of the nine Ric genes that are expressed in Arabidopsis pollen …