A representative for the Entertainment Software Association, which organizes the annual conference, tells us, "We can confirm that Take-Two Interactive Software is participating in E3 2013."
"We are going to have a meeting room in the upper concourse level and we'll be doing some business meetings as we usually do," a Take-Two spokesperson tells Joystiq. "2K is not participating."
As for Rockstar, the rebellious child of Take-Two, we're still waiting to hear official word if they plan to participate. Rockstar does not typically attend E3 and hasn't made any announcements.
2K's scheduled projects for this year include The Bureau: XCOM Declassified, Civilization V: Brave New World, XCOM: Enemy Unknown for iOS, more Borderlands 2 content, WWE 2K14 and NBA 2K14.