ok, let's establish certain facts first.
1) every individual expresses their own specific kind of isoform or
the Bullsht and Utter domains, which are able to dimerise
together.
2) when dimerised, the complex assumes its active form and is able
to bind to their own specific receptors (little is known about the
exact characteristic of the receptors, or how they recognise the
isoforms to such precise specificity.
a very recent research has elucidated a new
receptor--hisoka-recognising receptor, which specifically binds to
dimerised activated Utter Bullsht domain.
this triggers a cascade of signalling pathways that lead to
physiological and psychological effectors on the target tissues of
one particular organism, Sapien Starblue. the exact mechanism is
still under heavy construction.