I have read recently something on the lines that every Political Party in Parliament must, within its own Party's Constitution insist that the Country's Constitution is paramount ......and that they should not insist that its Parliamentary delegates, appointed by their Party in every instance, be instructed to vote against their conscience or indeed belief... and risk 'being victimized accordingly' through dismissal or even physical threat (ANC - KZN)
The ANC 's mantra seems clearly to be 'Party before Country' and any dissenting MP's run the risk of being fired! 
Mbete and Mthembu are no different in this respect, nor Mantashe, nor the rest of the ANC hierarchy.

Zuma's opinion matters not in the slightest in this instance.