PARsing embryonic polarity

Embryonic polarity and the PAR-1 molecule, the first to be found to play an important and perhaps conserved role in both D. melanogaster and C. elegans, are discussed in this minireview article. It is interesting to consider whether conserved mechanisms used for establishing embryonic polarity exist. The most significant blank space in understanding the function of PAR proteins has been information that links them to downstream localization events, that explains how they mediate asymmetric distribution of other molecules.