Twitter CEO Dick Costolo has quit his position as a U.K. director of the company, days after Twitter subsidiary TweetDeck was dissolved as a separate U.K. business by business registrar companies House. Costolo stepping back from the U.K. directorship role appears related to the dissolution of TweetDeck. Costolo’s position has been replaced by a Dublin-based chartered accountant, Laurence O’Brien.

Twitter, Inc. hired Cynthia Gaylor, a Morgan Stanley managing director who has focused on the internet, e-commerce, mobile and software sectors, to be head of corporate development.

Twitter, Inc. revealed plans to open a new office in Toronto. The company also announced it has hired Kirstine Stewart, formerly of CBC, as the managing director and first employee of Twitter Canada.