Support from professional with young dog (4,2)
I believe the answer is:
prop up
'support' is the definition.
(I know that prop up is a more specific form of the action support)
'professional with young dog' is the wordplay.
'professional' becomes 'pro' (abbreviation).
'with' is a charade indicator (letters next to each other).
'young dog' becomes 'pup' (short for puppy).
'pro'+'pup'='PROP UP'
'from' is the link.
(Other definitions for prop up that I've seen before include "Keep going" , "Support" , "Give financial backing" , "Underpin" .)