Vesicular trafficking, cytoskeleton and signalling in root hairs and pollen tubes.
Root hairs and pollen tubes show strictly polar cell expansion called tip growth. Recent studies of tip growth in root hairs and pollen tubes have revealed that small GTPases of the Rab, Arf and Rho/Rac families, along with their regulatory proteins, are essential for spatio-temporal regulation of vesicular trafficking, cytoskeleton organization and signalling. ROP/RAC GTPases are involved in a multiplicity of functions including the regulation of cytoskeleton organization, calcium signalling and endocytosis in pollen tubes and root hairs. One of the most exciting recent discoveries is the preferential localization of vesicles of the trans-Golgi network (TGN), defined by specific RAB GTPases, in the apical "clear zone" and the definition of TGN as a bona fide organelle involved in both polarized secretion and endocytosis. The TGN is thought to serve the function of an early endosome in plants because it is involved in early endocytosis and rapid vesicular recycling of the plasma membrane in root epidermal cells.
Samaj
Jozef
J
Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany. jozef.sama@uni-bonn.de
Müller
Jens
J
Beck
Martina
M
Böhm
Nils
N
Menzel
Diedrik
D
D000199:Actins / Q000502:physiology; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D004705:Endocytosis / Q000502:physiology; D050356:Lipid Metabolism; D008954:Models, Biological; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D053205:Pollen Tube / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D015398:Signal Transduction; D022161:Transport Vesicles / Q000502:physiology*; D021601:trans-Golgi Network / Q000378:metabolism / Q000502:physiology
D000199:Actins; D020559:Monomeric GTP-Binding Proteins; D002118:Calcium