Puts pressure on staff underpinning rents thus adjusted (5,3,5)

'puts pressure on' is the definition.
(to turns the screw is to apply pressure)

'staff underpinning rents thus adjusted' is the wordplay.
'staff' becomes 'crew' (crew of workers).
'underpinning' says to put letters next to each other (I've seen this in other clues).
'adjusted' indicates anagramming the letters.
'rents'+'thus'='rentsthus'
'rentsthus' with letters rearranged gives 'turnsthes'.
'crew' after 'turnsthes' is 'TURNS THE SCREW'.