Jenna is working as an informant for C-Sec on behalf of Detective Chellick. Jenna insists she can take care of herself, and gets annoyed when Commander Shepard tries to make her realise just how dangerous Chora's Den can be. She asks the Commander to leave so she can get back to work: "I'm not a stripper, I don't get paid to stand around and look pretty."
Shepard can help Jenna by co-operating with Chellick to close his investigation. In return, Chellick gets Jenna out of Chora's Den. She's hired back by Doran at once - apparently the customers at Flux love Jenna - but while Rita is happy her sister is out of danger, she'd forgotten that Jenna gets the best tips.
Mass Effect 3
If Shepard dealt with Jenna back in 2183, Jenna saves Conrad Verner's life, using an omni-tool trick she learned from Chellick to hack the gun of a Cerberus agent as Conrad leaps to take a bullet for Shepard. He and Jenna then get acquainted over his relationship with the Commander.