Plant GTPases: the Rhos in bloom.

In animal cells and in fungi, small GTP-binding proteins of the Rho family have well-established roles in morphogenesis, cell-cycle progression, gene transcription and the generation of superoxide anions. The presence of these proteins in plant cells, however, has been established only recently, and the role of Rho GTPases in plants is now coming into view. Already, it is apparent that there are both striking similarities and fascinating differences in how Rho GTPases are regulated and used in plant versus animal and fungal cells. These new findings define certain core properties that might be common to members of this protein family in all eukaryotes.