Allison Johnson, Apple’s vice president of worldwide marketing communications, is leaving the company for greener pastures, sources told John Paczkowski who broke the news on The Wall Street Journal’s Digital Daily blog. She played an important role in Apple’s worldwide advertising and reported directly to Steve Jobs, the man known for tight control of Apple’s marketing department.

No bad blood is brewing between Apple and Johnson as a result of her departure, sources said. The marketing whiz worked for the company since 2005, coming from Hewlett-Packard. Sources claim she’s leaving to start a new PR agency with Brandee Barker, a former Facebook PR person:

There’s nothing unusual to see a marketing expert depart a company like Apple.

I’ve seen it happening a lot in this industry.

Journalists leaving publishers to work as spokespeople for the companies they used to cover.

Most of them at some point leave their PR jobs, some due to burn out and others to start PR firms of their own.