ABSTRACT.    The cell subsurface of some unicellular cells is reinforced with a dense layer underlying the surface membrane, the epiplasm. The constitutive proteins of this layer were named epiplasmins or articulins, based on molecular organisation and cell studied. The hallmark of the articulins is a core domain composed of repetitive motifs of alternating valine and proline residues and a segregation of charged residues with respect to the V- and P- positions. This repeated 12 residues strech is termed VPV-motif. Articulins have been evidenced in Euglena, the apicomplex Cryptosporidium, and the ciliates Pseudomicrothorax dubius and Euplotes. Epiplasmins were mainly characterized in {Paramecium} in which they constitute a multigenic family with a very conserved central domain. We searched for articulins in the genome of Paramecium using the BLAST program, and two unknown proteins presented a synapomorphy with one domain of the Euglena articulin. These two paralogs of Paramecium show a main domain constituted of alternating charged residues and an enrichement in V and P residues but no 12-residues long motif. After an analysis of these motifs using the HCA (Hydrophobic Cluster Analysis) representation we defined a very constrained 8-mers: VPh[E,D][R,K]hh[E,D] (with h as hydrophobic residue); motif identifiable in the 12-mers of Euglena. This allowed us to establish a strong structural relationship between these proteins. This new pair of Paramecium proteins is composed of several domains with one identified as articulin and three putatives based on the hydrophobic characteristics. By microscopy, the expression of either one of these proteins fused to GFP as a reporter gene shows a localization to the base of cilia, at the level of the transition basal body/axoneme. This material localizes around the terminal plate in connection to the epiplasmic layer. The modular organization of this new protein, the presence of an articulin domain and the specific localization lead to attribute to this protein a role of connector between the cilia and the epiplasmic layer.