Plant cell division is specifically affected by nitrotyrosine.
Virtually all eukaryotic alpha-tubulins harbour a C-terminal tyrosine that can be reversibly removed and religated, catalysed by a specific tubulin-tyrosine carboxypeptidase (TTC) and a specific tubulin-tyrosine ligase (TTL), respectively. The biological function of this post-translational modification has remained enigmatic. 3-nitro-L-tyrosine (nitrotyrosine, NO(2)Tyr), can be incorporated into detyrosinated alpha-tubulin instead of tyrosine, producing irreversibly nitrotyrosinated alpha-tubulin. To gain insight into the possible function of detyrosination, the effect of NO(2)Tyr has been assessed in two plant model organisms (rice and tobacco). NO(2)Tyr causes a specific, sensitive, and dose-dependent inhibition of cell division that becomes detectable from 1 h after treatment and which is not observed with non-nitrosylated tyrosine. These effects are most pronounced in cycling tobacco BY-2 cells, where the inhibition of cell division is accompanied by a stimulation of cell length, and a misorientation of cross walls. NO(2)Tyr reduces the abundance of the detyrosinated form of alpha-tubulin whereas the tyrosinated alpha-tubulin is not affected. These findings are discussed with respect to a model where NO(2)Tyr is accepted as substrate by TTL and subsequently blocks TTC activity. The irreversibly tyrosinated alpha-tubulin impairs microtubular functions that are relevant to cell division in general, and cell wall deposition in particular.
Jovanović
Aleksandra M
AM
Institute of Botany 1 and Center for Functional Nanostructures, University of Karlsruhe, Kaiserstrasse 2, D-76128 Karlsruhe, Germany. jovanovic@kit.edu
Durst
Steffen
S
Nick
Peter
P
D002455:Cell Division / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D004136:Dinitrobenzenes / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects; D012275:Oryza / Q000378:metabolism; D010936:Plant Extracts / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D013424:Sulfanilamides / Q000494:pharmacology; D014026:Nicotiana / Q000166:cytology* / Q000254:growth & development; D014404:Tubulin / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
D004136:Dinitrobenzenes; D010936:Plant Extracts; D013424:Sulfanilamides; D014404:Tubulin; C039520:tyrosine-tubulin; C002744:3-nitrotyrosine; D014443:Tyrosine; C012465:oryzalin