Comic Garry Shandling, star of HBO’s “The Larry Sanders Show,” has joined United Talent Agency after departing CAA.Shandling will be repped by a team of agents led by Jim Berkus, Nick Stevens and Jeremy Zimmer. He will retain his longtime manager, Brad Grey. No reason was given for his decision to switch agents. He had been at CAA for about eight years. “Larry Sanders” will begin its sixth season when it goes back into production in October. In addition to his TV work, Shandling made a foray into features with the recent “Love Affair.” He has the feature “What Planet Are You From?” set up at Columbia.