| Abstract Detail
Conference Wide Damari-Weissler, Hila [1], Kandel- Kfir, Michal [1], Gidoni, David [1], Mett, Anahit [1], Belausov, Eddy [2], Granot, David [1]. Tomato hexsokinases and fructokinases have different intracellular locations. FOUR hexokinase (HXK) and four fructokinase (FRK) isozymes were identified in tomato plants. GFP fusion studies indicated that LeHXK4 and LeFRK3 are localized within plastids. Furthermore, both enzymes are also found in stromules and are probably transported between plastids. The surprised presence of FRK in plastids raises the unsolved question on the origin of fructose in these organelles. Truncated forms of LeFRK3::GFP and LeHK4::GFP that lack the predicted plastid transit peptides are excluded from the chloroplasts indicating that indeed these peptides determine the plastidic localization of LeFRK3 and LeHXK4. GFP fusion analysis indicates that the other three FRK (LeFRK1&2&4) isozymes are localized in the cytosol, while the three HXKs (LeHXK1,2&3) appear to be membrane associated. Accordingly, truncated forms of LeHXK1,2&3 that lack the membrane anchor domains were evenly dispersed in the cytoplasm. The distinct intracellular localization of HXK and FRK isozymes in the cytoplasm indicates that glucose and fructose phosphorylation takes place in different cytoplasmic sites. Glucose is phosphorylated only adjacent to membranes while fructose is phosphorylated either adjacent to membranes by HXKs or in the cytosol by FRKs.
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1 - Volcani Center, Vegetable Research, Bet Dagan, 50250, Israel
2 - Volcani Center, ARO, Bet Dagan, 50250, Israel
Keywords:
hexose phosphorylation
Fructokinase
hexokinase
GFP
Intracellular localization.
Session: Poster-144
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:343 |
