Activity and structure of human acetyl-CoA carboxylase targeted by a specific inhibitor.

We have studied a series of human acetyl-CoA carboxylase (ACC) 1 and ACC2 proteins with deletions and/or Ser to Ala substitutions of the known phosphorylation sites. In vitro dephosphorylation/phosphorylation experiments reveal a substantial level of phosphorylation of human ACCs produced in insect cells. Our results are consistent with AMPK phosphorylation of Ser , Ser , Ser , and Ser .

An amidase is required for proper intercellular communication in the filamentous cyanobacterium sp. PCC 7120.

Channels that cross cell walls and connect the cytoplasm of neighboring cells in multicellular cyanobacteria are pivotal for intercellular communication. We find that the product of the gene of the filamentous cyanobacterium sp. PCC 7120 is required for proper channel formation.

Requirement of Fra proteins for communication channels between cells in the filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120.

The filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 differentiates specialized cells, heterocysts, that fix atmospheric nitrogen and transfer the fixed nitrogen to adjacent vegetative cells. Reciprocally, vegetative cells transfer fixed carbon to heterocysts.

Anabaena cell ageing monitored with confocal fluorescence spectroscopy.

Cyanobacteria use a sophisticated system of pigments to collect light energy across the visible spectrum for photosynthesis. The pigments are assembled in structures called phycobilisomes, composed of phycoerythrocyanin, phycocyanin and allophycocyanin, which absorb energy and transfer it to chlorophyll in photosystem II reaction centres. All of the components of this system are fluorescent, allowing sensitive measurements of energy transfer using single cell confocal fluorescence microscopy.

Visualization of channels connecting cells in filamentous nitrogen-fixing cyanobacteria.

Cyanobacteria, formerly called blue-green algae, are abundant bacteria that carry out green plant photosynthesis, fixing CO2 and generating O2. Many species can also fix N2 when reduced nitrogen sources are scarce. Many studies imply the existence of intracellular communicating channels in filamentous cyanobacteria, in particular, the nitrogen-fixing species.