Several prominent real estate firms — from Minneapolis to Malaysia — have expressed interest in developing the top portion of a parking ramp that is part of the $400 million Downtown East project.

The 1,600-space, six-story ramp is a key part of an ambitious development proposed by Ryan Cos., which also includes two office towers for Wells Fargo & Co., up to 400 apartments, retail shops and restaurants, and a nearly two-block park on land now owned by the Star Tribune.

The $49 million ramp will ultimately be owned by the Minnesota Sports Facilities Authority, the body overseeing the nearby $1 billion Vikings stadium. But Minneapolis recently issued a request for proposals to develop for the “air rights” above the structure, as well as a strip of land facing S. 4th Street, across from a light-rail stop.

Possible uses that have been discussed for space above the ramp include a hotel or offices, while residential uses have been suggested for the liner parcel, as well as offices.

At a meeting of several downtown Minneapolis neighborhood groups Thursday night on the Downtown East development, several residents quizzed representatives from Ryan about the parcel that’s partly in play.

According to documents posted Thursday on the city’s website, a conference call with city officials was held on Monday for those interested in learning more about the project. Among those dialing in: the Ackerberg Group, the developer of the MoZaic office complex in Uptown; Sherman Associates, a long-standing local developer that has completed over $2 billion in real estate projects since 1979; Summit Hotel Properties Inc., which recently renovated the Centre Village building in Minneapolis into a Hyatt Place hotel, and Ryan Cos.

Other developers listening hailed from North Carolina, Colorado and even Malaysia. The Brunsfield International Group of Kuala Lumpur developed the 47-unit Brunsfield North Loop apartments in Minneapolis, considered an inventive project.

Proposals are due Feb. 4. There’s no telling whether any developers on the conference call will actually submit plans.

The city said in its request that it would like the project to contribute to the “vibrancy and livability in Downtown East through the inclusion of active ground floor uses and other public amenities such as retail, entertainment, and storefront commercial offices.”

Ryan plans to complete the ramp by the end of 2015.