Sheen Austin is out at Twitter. He joined the company via Tesla and took over infrastructure after Nelson Abramson.

NEW: Elon Musk emailed Twitter saying most of his Tesla work was completed this wknd & he’s available to discuss “urgent” product needs. All changes have to be signed off by him personally. “We are going to agonize until we achieve as close to the perfect product as possible”

Must says Twitter employees should schedule meetings on urgent product decisions, engineering progress, legal, finance and HR.