Besides, the former Tata brand custodian under Mistry's regime Mukund Rajan has been given the responsibility of overseeing operations of the overseas representative offices of Tata Sons in the USA, Singapore, Dubai and China.
This is in addition to his existing responsibility of ethics and sustainability.
Harish Bhat, who is responsible for marketing and customer centricity, will henceforth also be responsible for managing the Tata Brand, Tata Sons said in a statement.
"In the interim, he will oversee the functions of Strategy and Business Development," it added.
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Tata Sons further said Gopichand Katragadda will continue to be the Group Chief Technology Officer, while Sanjay Singh will oversee the Public Affairs function out of the Delhi office.
Three members of the now-disbanded Group Executive Council set up by Mistry -- Nirmalya Kumar, N S Rajan and Madhu Kannan -- have already quit.
They have decided to explore options outside Tata Sons and have left the services of the company, the statement added.
On October 24, Tata Sons board had replaced Mistry as Chairman and appointed Ratan Tata as interim Chairman. The company had said it would find a new Chairman in four months.
Tata retorted saying Mistry's removal was "absolutely necessary" for the future success of the Tata Group and insisted that the decision was a well-considered and serious one for its board members.