is there a way of communication between main loop's objects' signals and thread objects' slots and vise versa.

For example:
main() has:
obj1 has signal1
obj2 has slot slot2

thread
tread.start()
-----------------------------------------------------------

thread has:
obj3 has signal3
obj4 has slot4
-----------------------------------------------------------

is it possible to call slot2 when signal3 emitted?
is it possible to call slot4 when signal1 emitted?