A partner at Proskauer Rose told a Washington, DC federal court on Monday that "rank-and-file" partners at her firm function as employees, not business owners, and the court should therefore reject Proskauer's bid to dismiss her $50m (£38m) gender bias lawsuit.

Lawyers for the Jane Doe plaintiff at Sanford Heisler Sharp filed a flurry of papers opposing the firm's motions for dismissal and summary judgment. The suit alleges that Doe was paid less than male counterparts, despite excelling as a partner, and that the firm marginalised her when she complained about unequal pay.

Proskauer argued in June that the complaint sought to shoehorn claims by a disgruntled but highly paid equity partner into federal and state anti-discrimination laws that are really meant to protect employees who hold no ownership stake in a business. The firm also dismissed the claims of bias and retaliation as "utter falsity".

Doe's legal team, led by Sanford Heisler Sharp's David Sanford, countered on Monday that far from acting as "business owners", Doe and other partners at the firm work under strict rules and policies that Proskauer's executive committee determines. The executive committee also determines the partners' pay and controls hiring and firing, the lawyers argued.

"The control vested in and exercised by the executive committee creates a substantial separation between the firm and its rank-and-file partners," Sanford argued. "It is the executive committee that controls firm partners, not the other way around."

In a statement on Monday, Proskauer said the plaintiff was fairly rewarded for her work at the firm and "treated properly at every turn".

"Despite the many false statements in her papers, nothing in Ms Doe's opposition changes the fact that she is a business owner who is not covered by the laws she seeks to invoke," the statement said.

The partner opted to sue as a Jane Doe plaintiff for several reasons, including a concern that psychological and medical symptoms documented in the suit may damage her professional reputation, according to a brief filed along with the original complaint in May. Her lawyers also pointed to a period of family leave she took in order to care for a child with health problems; the suit alleges that Proskauer retaliated against the woman after she took that time off.

Kathleen McKenna, a Proskauer partner, is leading the firm's defense alongside fellow partner Evandro Gigante. Both are also facing plaintiffs lawyers from Sanford Heisler Sharp in a separate gender bias lawsuit in New York brought by women who formerly served as partners at Chadbourne & Parke, which recently combined with global firm Norton Rose Fulbright.