President Obama with White House Chief of Staff Jack Lew. (Mandel Ngan/AFP/Getty Images)

Lew’s X factor — A closer look at White House Chief of Staff Jack Lew — who is President Obama’s pick to be treasury secretary — and the time he spent at the helm of a division of Citigroup during a stormy time.

Staffing shakeup — It’s finally a go ... after waiting in the wings for a while, President Obama plans to announce Denis McDonough as Lew’s replacement today, as well as a slew of other senior-staff promotions.

More moves — Chris Lu, the White House official tasked with coordinating with the Cabinet, is leaving the job. No word yet on a replacement or where he’s heading.

Fly guy — Obama is plagued by a fly ... and not for the first time.