Pattern formation in single cells

Single-cell patterning begins with an asymmetric cue that orients the axis of polarity. Despite great diversity in the types of cues, common mechanism s appear to mediate the polarizing response. Rho-family GTPases initially p rocess and reinforce polarity cues by remodelling, cortical actin, and thes e Local asymmetries are subsequently propagated to the microtubules, membra ne and secretory pathway to generate the final pattern. Homologues of the y east polarity genes fulfil similar functions in higher eukaryotes, revealin g a fundamental conservation in how polarity arises. Unlike yeast, however, more complex eukaryotic cells can manifest multiple axes of polarity, sugg esting that additional mechanisms have evolved to generate more elaborate p atterns.