Transpeptidase that recognizes and modifies its substrate by proteolytic cleavage of a sorting signal. Following cleavage, a covalent intermediate is formed via a thioester bond between the archaeosortase and its substrate, which is then transferred and covalently attached to the cell membrane (Probable). This sortase recognizes a tripartite structure consisting of a conserved Pro-Gly-Phe (PGF) motif, followed by a transmembrane alpha helix domain and a cluster of basic residues, usually at the C-terminus of target proteins (Probable). Confirmed substrates include the cell surface S-layer glycoprotein Csg and HVO_0405 (PubMed:23651326, PubMed:26712937, PubMed:28069824). ArtA is required for the C-terminal processing of Csg and for its lipidation and attachment to the archaeal plasma membrane (PubMed:23651326, PubMed:26712937). It is also required for the processing of HVO_0405, which contains an atypical central tripartite structure (PubMed:28069824). Deletion of the gene results in poor growth, especially under low-salt conditions, alterations in cell shape and in the S-layer, impaired motility and impaired conjugation. Belongs to the exosortase/archaeosortase family. Archaeosortase A subfamily.