Profilin

Profilin, a small ubiquitous nonmuscle protein of 12-14 kDa, is found in eukaryotic cells (Carlsson et al. 1977; Reichstein and Korn 1979) including plants (Valenta et al. 1992), and viruses (Machesky et al. 1994) (see chapter by Bearer). It is expressed in all eukaryotic organisms studied to date. Profilin is essential for the normal development and cytokinesis of 'Dictyostelium' Amoeba (Haugwitz et al. 1994). These authors showed that in profilin-null mutants cell motility was significantly reduced and development was blocked prior to fruiting body formation. Furthermore, these cells could not be grown in shaking culture under normal conditions. In 2001, profilin 1 was also shown to be essential for cell survival and cell division in mice (Witke et al. 2001). Specifically, profilin 1 double knockout... embryos died as early as the two-cell stage, and... blastocycsts were not detectable. Although profilin has been intensely studied since its discovery nearly 20 years ago, its 'in vivo' functions are still poorly understood. Only recently has research highlighted the role of profilin in diseases such as cancer (Janke et al. 2000; Roy and Jacobson 2004; also see chapter by Van Troys) and Parkinson's disease (Basso et al. 2004), although its involvement as an allergen has been known since the early 1990s (Valenta et al. 1991a,b). In this chapter, the role of profilin in these disorders will be reviewed and discussed.