Inside-out but not right side-out plasma membrane vesicles from soybean enlarge when treated with ATP + 2,4-D as determined by electron microscopy and light scattering: evidence for involvement of a plasma membrane AAA-ATPase.
The concept that the location of an AAA-ATPase associated with the plant plasma membrane may be indicative of a functional relationship to growth or cell enlargement by analogy with roles in physical membrane displacements as proposed for AAA-ATPases associated with internal membranes was tested. A plant growth hormone-responsive and nucleoside triphosphate-dependent enlargement of inside-out vesicles of plasma membranes from soybeans was utilized in a completely cell-free system. The rate of enlargement was accelerated by the synthetic plant growth factor 2,4-dichlorophenoxyacetic acid (2,4-D) in a log dose-dependent manner and was increased approximately 2-fold with the addition of 1 microM 2,4-D plus 100 microM ATP compared to 100 microM ATP alone, 1 microM 2,4-D alone or no additions. The cell-free enlargement was inhibited by AAA-ATPase-specific antisera and by CoCl2, an inhibitor specific for AAA-ATPases. The responsible ATP site appears to be on the inside of the cell, since right side-out vesicles did not enlarge in response to either ATP, 2,4-D or the two in combination.
Hicks-Berger
Carrie
C
Morré
D James
DJ
D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology*; D048430:Cell Shape; D008027:Light; D008666:Metalloendopeptidases / Q000378:metabolism*; D008854:Microscopy, Electron; D013025:Glycine max / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*
D015084:2,4-Dichlorophenoxyacetic Acid; D000255:Adenosine Triphosphate; D008666:Metalloendopeptidases; C114583:m-AAA proteases