Research of plant RHO-type (ROP) GTPases has considerably accelerated during the last few years. Now it is clear that these small proteins play central roles as signalling molecules during many basic cellular processes including cell shape determination, polar growth and responses to hormones, stress factors or pathogens. ROP GTPases have the potential to interact with a plethora of regulators and effectors that finally determines their signalling specificity. These proteins, similarly to the ROP GTPases themselves, are coded by small gene families increasing the complexity of the regulation. The comparison of gene expression patterns of the individual members of these gene families may help to reveal potential signalling chains with biological relevance. In this review previous observation on the differential expression of ROP GTPase genes in various organs and during various developmental processes is summarized. In addition, an inventory of presently known ROP GTPases-interactor proteins is provided with brief descriptions and with correlative comparison of gene expression patterns based on available microarray data.