Uber has revealed that its head of communications will leave the company, her exit is the latest in a steady stream of executive departures that goes all the way to the firm's president.
Uber CEO Travis Kalanick did not say why Rachel Whestone resigned in an email to employees.
"I wanted to let you know that Rachel Whetstone, who heads up policy and communications globally, has decided to leave Uber,” Mr Kalanick wrote.
"Since joining in 2015, Rachel has blown us all away with her ability to get stuff done. She is a force of nature, an extraordinary talent and an amazing player-coach who has built a first-class organization."
Ms Whetsone's resignation comes less than a month after Uber's former CEO Jeff Jones quit less than six months into the role.
At the time Mr Jones said that his approach to leadership was at odds with the way the company operated.
But executive resignations have not been Uber's only problem. In February Chief Executive Travis Kalanick was at the centre of controversy after a video was released showing him berate an Uber driver who complained about cuts to drivers' rates.
That came only days after former engineering executive Amit Singhal was asked to resign amid sexual harassment claims from his time at Google.
Uber's vice president of maps and business platform, Brian McClendon, also left the company at the end of last month to pursue a career in politics in his home state of Kansas.
Also last month, director Raffi Krikorian of Uber's self-driving division announced that he had quit.
Besides from a number of high-level departures, Uber is also the subject of a lawsuit from Google's self-driving car division that accuses the company of stealing designs for autonomous car technology.
Uber denies the claims.