The Compartments And Complexity In The Eukaryotic Cell

The study showing the compartments and complexity in the cell; this showing the closer look at the subcellular distribution of the proteins; and metabolic intermediates in a model plant. The results of the study provide new insights into the dynamics of metabolic processes in cells. Eukaryotic cells in this context; plant cells contain a variety of subcellular compartments in which specific sets of enzymatic reactions take place.

In addition to the classical organelles, which are delimiting by intracellular membranes; the soluble phase of the cytoplasm is the site of defined metabolic transformations. How metabolic processes in these diverse compartments are regulated and coordinated is poorly understanding. Study succeeding in quantifying the subcellular distribution of a broad range of proteins and metabolites in leaf cells; thus revealing new aspects of the metabolic dynamics in these cells.

Complexity in the eukaryotic cell

It is often the case that the effects of environmental factors on plant metabolism can only be vaguely characterized, because plant cells cannot be interrogated with the necessary precision; For example, if certain products of metabolism accumulate in response to environmental stress; it has not been possible to determine where exactly in the cell they actually build up whether in the fluid filled plant vacuole which serves as a storage compartment; in the mitochondrion which supplies the cell with energy; in the cytosol where many metabolic reactions take place, or somewhere else.

But the study modifying a conventional method knowing as non-aqueous fractionation to make it compatible with high-throughput analyses. With this approach, cells can be dismantling into their component compartments; and the contents of each can be separately analyzed. The novel fractionation strategy enabled the LMU researchers to show that a disabling mutation in the cytosolic enzyme hexokinase has a significant impact on processes that occur in chloroplasts (the sites of photosynthesis) and mitochondria.

Phosphorylation of carbohydrates

Hexokinase catalyzes the phosphorylation of carbohydrates. In doing so, it enables the production of intermediates required for many other metabolic pathways including plant respiration. “Our results demonstrate that glucose accumulates in the cytosol when the hexokinase is defective and this is accompanied by a rise in the level of glucose in the vacuole; while concentrations of the amino acids glycine and serine in the mitochondria are significantly reducing.

These two amino acids are central intermediates in an important metabolic pathway knowing as the photorespiration; which essentially counteracting photosynthesis and is stimulating in particular by drought stress. Therefore, the mutation in hexokinase most probably reducing the photorespiratory capacity of the cell. This assumption is supporting by further analysing of the impact of the mutation on proteins that are knowing to play an important role in mediating photorespiration.