Intracellular targeting of the proteasome.

Proteasomes are soluble, but can also be found in association with subcellular organelles. Adaptors capable of mediating interactions between proteasomes and intracellular organelles have not yet been identified, although they might exist. Although most proteasomal substrates are soluble, some membrane-bound proteins are also degraded by the proteasome. Processing of such insoluble substrates might cause proteasomes to be organelle-bound by tethering the degradative apparatus to the organelle.