We have identified alveolar sac associated proteins of alveolates and characterised a novel protein family, namely Alveolins. These proteins are encoded by gene families ranging from two genes in the ciliate Tetrahymena thermophila to more than a dozen as found in the apicomplexan parasite Toxoplasma gondii. They are highly soluble and predicted to form coil-coiled domains. In Plasmodium falciparum we were able to show they interact with proteins embedded in the alveolar membrane. We are the first to provide the molecular nexus uniting this super group. Proteomic profiling of the isolated pellicle from Tetrahymena thermophila has not only given us an insight into the proteomic content of this complex structure, but furthermore led to the identification of a remarkable feature found in many known and so far unknown proteins of the alveolate pellicle. More than a third of the proteins predicted to localise to the pellicle were found to contain charged repetitive motifs. These motifs vary in length, amount and distribution, and are present in many major proteins of the cytoskeleton/ pellicle of the ciliate T. thermophila. We have managed to localise several ,hypothetical proteinsʻ we identified in our screen and could show they belong to different cell-structures, but are always associated with the pellicle. We have started to search for homologs in other Alveolata with focus on apicomplexan parasites and identified many intriguing and potentially new protein-families. The localisation of one of the homolog proteins in T. gondii has led to the identification of the first conoid-ring protein and is consistent with our working hypothesis that Alveolata share many pellicle proteins and that charged repeat motifs are involved in the design of many of these structural proteins.