Similar to phosphorylation or
dephosphorylation cycles, ubiquitylated
proteins can also be de-ubiquitylated by
specific enzymes to reverse their fate.
Such ubiquitin proteases and ubiquitin
carboxyl-terminal hydrolases are
expected to play a regulatory role and
may provide additional complexity to
hormone signaling. So far, no hormone-
signaling mutants affected in such
enzymes have been reported.