For example, the Ran GEF, RCC1, is present in the nucleus while the Ran GAP is present in the cytosol, modulating nuclear import and export of proteins.
IgG also plays an important role in antibody-dependent cell-mediated cytotoxicity (ADCC) and intracellular antibody-mediated proteolysis, in which it binds to TRIM21 (the receptor with greatest affinity to IgG in humans) in order to direct marked virions to the proteasome in the cytosol.
ER-proteins are degraded in the cytosol by the 26S proteasome, a process known as Endoplasmic-reticulum-associated protein degradation, and therefore have to be transported by an appropriate channel.