title: Signaling mechanisms in the establishment of plant and fucoid algal polarity.
abstract: The establishment of polarity is a fundamental property of most cells. In tip-growing plant and in fucoid algal cells, polarization specifies a growth pole, the center of localized secretion of new plasma membrane and cell wall material, generating a protrusion with a dome-shaped apex. Although much progress has been made concerning the cellular machinery required to execute tip growth, less is known regarding the signaling mechanisms involved in selecting the growth site and regulating vectorial cell division and expansion. Fucoid algal zygotes use extrinsic cues to orient their growth axes and are thus well-suited for studies of de novo selection of an axis. This process has been investigated largely by both pharmacological and immuno-localization studies. In tip growing plant cells, polarity is often predetermined, as in the formation of root hairs or moss protonema branches. More focus has been on genomic and genetic studies to reveal the molecules involved in expressing a growth axis. Here we review the common roles of the cytoskeleton and signal transduction pathways in the formation of a developmental axis in fucoid algal cells and the control of tip growth in higher plant cells.
authors.affiliation: University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, USA. whable@umassd.edu
authors.forename: Whitney E
authors.initials: WE
authors.lastname: Hable
authors.forename: Peter E
authors.initials: PE
authors.lastname: Hart
mesh_terms: D000199:Actins / Q000502:physiology; D002118:Calcium / Q000032:analysis / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology*; D003599:Cytoskeleton / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000502:physiology; D008870:Microtubules / Q000502:physiology; D000459:Phaeophyceae / Q000502:physiology*; D018521:Plant Physiological Phenomena; D015398:Signal Transduction / Q000502:physiology*; D015053:Zygote / Q000502:physiology
chemical_list: D000199:Actins; D020558:GTP Phosphohydrolases; D002118:Calcium