Newly identified plant proteins may shed light on the evolutionary process

A group of nuclear-envelope-associated proteins have been found in a plant for the very first time by a team of researchers at Ohio State University. Led by Professor Iris Meier, this new finding show that these proteins (Plant RanGAP and MAF) have in common a nuclear envelope-targeting domain which is unique to plants and distinctly different from sequences found in known animal nuclear envelope proteins.

This finding is significant because it implies that a funadamentally different nuclear-envelope-targeting mechanism has evolved in the plant and animal kingdom. Plants and animals have evolved separately for about 1 billion years and this present finding implies that there are larger differences in the mechanisms by which cells organise their compnonents that was previously thought. How a cell orchestrates where and when its components are organised influences the very development, cell division and proliferation of that cell.

Plant ranGAP and MAF bind to proteins with large coiled-coil domains which are present in the nuclear envelope and resemble closely proteins which are present in the nuclear envelope of animal cells – called Lamins. Lamins control the structure of animal cells as well as gene regualtion (in particulr, linked to the development and deterioration of cells and ageing) but in animal RanGAP does not interact with the Lamin proteins as in plants. This has important evolutionary significance since it shows that, although the large coiled-coil proteins are present in both systems their sequences have not been conserved and they are performing different roles.

On Friday 18 July, at the Society for Experimental Biology’’s conference in Durham, Professor Meier will present preliminary results of a comprehensive analysis of all large coiled-coil proteins in Arabidopsis to establish their predicted localisation and functioanl domains and to establish a database which will be made available publicly