| Primary Identifier | IPR044685 | Type | Family |
| Short Name | ARC6-like |
| description | This family represents plant Protein ACCUMULATION AND REPLICATION OF CHLOROPLASTS 6 (ARC6) and its paralogue PARC6, components of the plastid division machinery which are essential for the chloroplast replication process [, ]. ARC6 is evolutionarily related to the cyanobacterial cell division protein Ftn2/ZipN [], being unique to the division machineries of cyanobacteria and chloroplasts. Their sequences share about 19% identity and are quite conserved along their length. Chloroplast division implies the assembly and constriction of the tubulin-like FtsZ ring on the stromal surface of the inner envelope membrane (IEM) and the dynamin-like ARC5 ring on the cytosolic surface of the outer envelope membrane (OEM). The assembly of these structures is coordinated by a pair of paralogous proteins, ARC6 and PARC6 from the IEM, and PDV2 and PDV1 from the OEM. They contain single transmembrane (TM) domains towards their C terminus with short C-terminal regions extending into the intermembrane space (IMS) [, , , , ]. Crystal structure of ARC6 showed that it comprises a chloroplast transit peptide, cleaved after chloroplast localisation, followed by a stroma-facing, a transmembrane and IMS regions. The C-terminal IMS is highly conserved in ARC6 and Ftn2 proteins []. ARC6 interacts with FtsZ and PDV2 through its stromal and IMS regions, respectively. ARC6-PDV2 interaction is key for PDV2 localisation to the division site and to specify the site of ARC5 recruitment []. PARC6 and PDV1 interact and function in the same way as ARC6-PDV2 [, ].This entry also includes ARC6 homologues from cyanobacteria. |
