Shows anger at parents in the van (5,2)

'the van' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'shows anger at parents' is the wordplay.
'shows anger' becomes 'up' (I can't explain this - if you can you should give a lot more credence to this answer).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'parents' becomes 'rears' ('rear' can be a synonym of 'parent').
'up' after 'rears' is 'REARS UP'.

'in' is the link.

Can you help me to learn more?