Continue to maintain you remain informed on (4,2)
I believe the answer is:
keep up
'continue' is the definition.
(keeping up is a kind of continuing)
'maintain you remain informed on' is the wordplay.
'maintain' becomes 'keep' ('keep' can be a synonym of 'maintain').
'you' becomes 'u' (I've seen this in other clues).
'remain informed' becomes 'p' (I can't explain this - if you can you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other).
'keep'+'u'+'p'='KEEP UP'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for keep up that I've seen before include "Match pace or store aloft" , "Stay with the pace, don't fall behind" , "Stick with" , "Stay in contention" , "Maintain pace with, don't lag behind" .)