UEFA handed a three-match European ban to Mourinho after he made allegations of favouritism towards bitter rivals and Champions League conquerors Barcelona.
Mourinho, already banned from the touchline for Tuesday's Champions League semi-final second leg at Camp Nou, which cemented Real's exit 3-1 on aggregate, will have a further one-match ban suspended for three years.
Karanka said Mourinho "would defend himself until the end" and announced that the outspoken Portuguese would make no further media appearances until European football's governing body justified the sanction against him.
"UEFA is the one imposing the punishment and as of today they have not said the reason why the coach was punished," Karanka told a post-training session news conference.
"The idea is that until it is specified or (UEFA) comes out with a more concrete reason, he will not appear."
UEFA's Control and Disciplinary Body found that a string of comments from Mourinho alleging that Barcelona benefited from decisions in their favour at their rivals' expense had constituted "inappropriate statements".
The Portuguese coach, who had been hoping to become the first man ever to coach three teams to the European Cup after previous successes with FC Porto and Inter Milan, was also fined 50,000 euros ($72,500).
Real defender Pepe, who was red-carded in the first leg, received a one-match ban but UEFA said it would consider this already served as he did not feature in the return leg.
Real furthermore received a 20,000 euro fine for poor conduct by their supporters.
Barcelona reserve goalkeeper Jose Pinto, red-carded in a half-time melee in the first leg, received a three-match ban.
It means he cannot take part in the Champions League final on 28 May against Manchester United, nor the first UEFA club competition match that Barca play next season.
Both clubs may appeal their punishments within three days and Real said they would do so, describing their punishment as heavy-handed and "defective" in that it did not afford Mourinho a chance to defend his behaviour.
The club added that "the exact statements for which the disciplinary case was opened and for which he has been punished are still unknown".
Mourinho unleashed a tirade against Barca, where he started out as a translator to former coach Bobby Robson 14 years ago.
"I don't know if it's the Unicef (Barca's sponsor) publicity or the friendship of (Spanish football federation chief Angel) Villar at UEFA, where he is vice-president," Mourinho said.
"I don't know if it's because they are so nice, but they have got great power. The rest of us have no chance.
"They are a great team, so congratulations to them, but they have this power. Pepe sent off and me too. I don't know why."
He also directed barbs at Barca counterpart Pep Guardiola, saying: "I would be embarrassed to win the Champions League like this."