Characterization of a 100-kDa heat-stable microtubule-associated protein from higher plants.
In higher-plant cells, the different cell-cycle-dependent microtubule arrays are involved in a wide range of activities including chromosome segregation, cell-plate formation and cellulose microfibril distribution and orientation. A wealth of data, obtained using animal cells, has indicated that the differential stability and function of microtubules during cell-cycle and/or differentiation could be primarily regulated by selective microtubule-associated proteins (MAP). Compared to animal MAP, our knowledge of plant MAP is so far very limited. In this study, we have identified a maize heat-stable protein with apparent molecular mass 100 kDa (P-100) which binds to taxol-stabilized neurotubules and copolymerizes in vitro with purified neural tubulin. Moreover, P-100 cross-reacts with affinity-purified tau antibodies like a maize 83-kDa putative MAP described previously [Vantard, M., Schellenbaum, P., Fellous, A. & Lambert, A. M. (1991) Biochemistry 30, 9334-9340]. Polyclonal antibodies directed against P-100 were obtained and indicated that this protein is found in diverse higher-plant cultured cells suggesting the ubiquitous nature of this protein. P-100 can be phosphorylated in vitro by protein kinases present in a maize cytosol extract. Together, our data suggest that P-100 could be a higher plant MAP.
Vantard
M
M
Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université Louis Pasteur, Strasbourg, France.
Peter
C
C
Fellous
A
A
Schellenbaum
P
P
Lambert
A M
AM
D015153:Blotting, Western; D002478:Cells, Cultured; D000939:Epitopes; D006358:Hot Temperature; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000737:chemistry*; D014404:Tubulin / Q000378:metabolism; D003313:Zea mays
D000939:Epitopes; D008869:Microtubule-Associated Proteins; D010750:Phosphoproteins; D010940:Plant Proteins; D014404:Tubulin