Former Chief Executive Officer Jack Dorsey has stepped down from the Twitter board of directors.The announcement came on Wednesday --the same day that Twitter held its annual shareholder meeting.Dorsey did not stand for re-election Wednesday, and is no longer a board member, ending his formal relationship with the social network he co-founded in 2006. He has been a director since 2007, and was most recently Twitter CEO from mid-2015 until his resignation last year. He had handed over the role to India's Parag Agrawal. At that time, the company noted that Dorsey would stay on the board "until his term expires at the 2022 meeting of stockholders." But now Dorsey’s exit marks the first time in Twitter’s history that none of its co-founders is working at the company, or sitting on the board.Twitter shareholders voted on a number of issues Wednesday, but didn’t weigh in on the biggest change confronting the San Francisco-based company: a looming buyout by billionaire Elon Musk. Twitter’s board accepted an offer from Musk in late April to take the company private for about $44 billion. The shareholder vote on whether to approve the deal will take place at a later date that hasn’t yet been announced.Musk, the world’s richest person, has pledged dramatic changes at Twitter once he takes over, and the current board isn’t expected to stay in place once he takes the company private.