| 1. |
- Kjellbom, Per, et al.
(författare)
-
Aquaporins and water homeostasis in plants
- 1999
-
Ingår i: Trends in Plant Science. - 1360-1385. ; 4:8, s. 308-314
-
Forskningsöversikt (refereegranskat)abstract
- Aquaporins are water channel proteins of vacuolar and plasma membranes. When opened they facilitate the passive movement of water molecules down a water potential gradient. In Arabidopsis, 30 genes have been found that code for aquaporin homologues. Some of these genes code for highly abundant constitutively expressed proteins and some are known to be temporally and spatially regulated during development and in response to stress. The water transport activity of two aquaporins is regulated at the protein level by phosphorylation and dephosphorylation. At a given time, cells express several different aquaporins, and it is probable that vacuolar and plasma membrane aquaporins acting in concert are responsible for the cytosolic osmoregulation that is necessary for maintaining normal metabolic processes. Inhibition studies of aquaporins in vivo and antisense mutant studies suggest that, in addition to cytosolic osmoregulation, aquaporins are important for the bulk flow of water in plants.
|
|
| 2. |
- Møller, Ian M., et al.
(författare)
-
The role of NADP in the mitochondrial matrix
- 1998
-
Ingår i: Trends in Plant Science. - 1360-1385. ; 3:1, s. 21-27
-
Tidskriftsartikel (refereegranskat)abstract
- Many diverse metabolic processes are coupled to the turnover of the coenzyme NADP in the matrix of plant mitochondria. NADPH can be produced via the NADP-specific isocitrate dehydrogenase as well as via enzymes like NAD-malic enzyme, NAD-malate dehydrogenase and Δ1-pyrroline-5-carboxylate dehydrogenase. Although not NADP-specific, the latter enzymes can all catalyse the reduction of NADP+ at appreciable rates. The NADPH produced can be used in folate metabolism, by glutathione reductase for protection against oxidative damage, and by thioredoxin reductase in the (putative) regulation of metabolic pathways via thiol-group reduction. It can also be oxidized by the respiratory chain via a Ca2+-dependent NADPH dehydrogenase - this is a potential way of regulating the NADP reduction level in the matrix and thus, indirectly, the other processes. It is now possible to present an integrated picture of NADP turnover inside the mitochondrion.
|
|
| 3. |
|
|
| 4. |
- Sjöling, Sara, et al.
(författare)
-
Mitochondrial targeting peptides in plants
- 1998
-
Ingår i: Trends in Plant Science. - 1360-1385 .- 1878-4372. ; 3:4, s. 136-140
-
Tidskriftsartikel (refereegranskat)abstract
- Proteins function at distinct sites in the cell, yet most are primarily synthesized in the cytosol and must therefore be transported intracellularly to their final destination. Mitochondrial targeting peptides are localized at the N-terminus of the precursor proteins and most are cleaved off after import into mitochondria. Cleavage is catalysed by the general mitochondrial processing peptidase, which, in plants, is integrated into the bc1 complex of the respiratory chain. This peptidase recognizes the cleavage sites of nearly 1000 precursor proteins that have no sequence similarity.
|
|
| 5. |
- Huner, Norman P. A., et al.
(författare)
-
Energy balance and acclimation to light and cold
- 1998
-
Ingår i: Trends in Plant Science. - 1360-1385 .- 1878-4372. ; 3:6, s. 224-230
-
Forskningsöversikt (refereegranskat)abstract
- Changes in environmental conditions such as light intensity or temperature result in an imbalance between the light energy absorbed through photochemistry versus the energy utilized through metabolism. Such an energy imbalance is sensed through alterations in photosystem II excitation pressure, which reflects the relative reduction state of the photosystem. Modulation of this novel, chloroplastic redox signal either by excess light or by low temperature initiates a signal transduction pathway. This appears to coordinate photosynthesis-related gene expression and to influence the nuclear expression of a specific cold-acclimation gene, plant morphology and differentiation in cyanobacteria. Thus, in addition to its traditional role in energy transduction, the photosynthetic apparatus might also be an environmental sensor.
|
|
| 6. |
- Jansson, Stefan, 1959-
(författare)
-
A guide to the Lhc genes and their relatives in Arabidopsis
- 1999
-
Ingår i: Trends in Plant Science. - 1360-1385 .- 1878-4372. ; 4:6, s. 236-240
-
Forskningsöversikt (refereegranskat)abstract
- The Lhc super-gene family encodes the light-harvesting chlorophyll al b-binding (LHC) proteins that constitute the antenna system of the photosynthetic, apparatus, and also includes some relatives whose functions are more or less unknown. The Lhc super-gene family of Arabidopsis contains >30 members and the databases contain >1000 EST clones originating from these genes. This article presents an overview of these genes and provides some tools for researchers who want to use them in their studies.
|
|
