[2][3] AAA proteins couple chemical energy provided by ATP hydrolysis to conformational changes which are transduced into mechanical force exerted on a macromolecular substrate.

[4] AAA proteins are functionally and organizationally diverse, and vary in activity, stability, and mechanism.

They are involved in processes such as DNA replication, protein degradation, membrane fusion, microtubule severing, peroxisome biogenesis, signal transduction and the regulation of gene expression.

[5] AAA proteins are divided into seven basic clades, based on secondary structure elements included within or near the core AAA fold: clamp loader, initiator, classic, superfamily III helicase, HCLR, H2-insert, and PS-II insert.

Prokaryotes have AAA which combine chaperone with proteolytic activity, for example in ClpAPS complex, which mediates protein degradation and recognition in E. coli.

In HslU, a bacterial ClpX/ClpY homologue of the HSP100 family of AAA proteins, the N- and C-terminal subdomains move towards each other when nucleotides are bound and hydrolysed.

Multivesicular bodies are endosomal compartments that sort ubiquitinated membrane proteins by incorporating them into vesicles.

It had originally been identified as a ”class E” vps (vacuolar protein sorting) mutant and was subsequently shown to catalyse the dissociation of ESCRT complexes.

AAA proteases use the energy from ATP hydrolysis to translocate a protein inside the proteasome for degradation.