Polarized growth: maintaining focus on the tip

Curr Opin Plant Biol. 2006 Dec;9(6):579-88. doi: 10.1016/j.pbi.2006.09.014. Epub 2006 Sep 28.


Tip growth, a spatially focused cell expansion, has been best characterized in two plant cell types: pollen tubes and root hairs. It has long been established that both cell types require three intracellular components for this process: a tip-high calcium gradient, a polarized actin cytoskeleton, and tip-directed vesicle trafficking. More recently, additional mechanistic parallels have been observed between the two cell types, including roles for ROP and Rab GTPase signaling, phosphoinositides, calcium-dependent protein kinases, and the exocyst. Uncovering pathways that control the three components is beginning to reveal a highly interconnected network, which we call the tip growth LENS (for localization enhancing network, self-sustaining), that coordinates the required cellular activities to allow regulated tip growth, and to maintain itself as the tip advances.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Calcium / metabolism
  • Cell Polarity*
  • Plant Cells*
  • Plant Development*
  • Plant Proteins / metabolism
  • Plant Roots / cytology
  • Plant Roots / growth & development


  • Plant Proteins
  • Calcium