John Hoffman (right) laughs with Hamza Suria (third from left) as they dine with friends, including Dominic Piscitelli (left) at Reveille Coffee. Photo: Gabrielle Lurie, The Chronicle
Photo: Gabrielle Lurie, The Chronicle

“When we came outside to look at the sign, there were five or six people watching us on the sidewalk,” said Nani Segaye, co-owner of the restaurant. “They said they couldn’t believe that we were coming. They were very excited. That made me happy.”

Mission Bay is a neighborhood that has exceeded expectations in many ways — in just 12 years it has become home to dozens of life-science companies, a new $1.5 billion hospital, acres of new green space, thousands of new housing units and the future Warriors arena. So it is telling that a flimsy cardboard sign announcing a new restaurant should be a cause of celebration. For years dining and retail have been been the neighborhood’s weak spots, with dust gathering in the empty ground floors of buildings even as the apartments upstairs fill with residents.

But slowly — some residents would say far too slowly — businesses are beginning to take a chance on Mission Bay.

This is especially evident on the 1100 block of Fourth Street, where House of Tadu, which plans to open in early August, is one of five businesses that have signed leases on the ground floor of an affordable apartment complex owned by Mercy Housing. Next door will be Casey’s Pizza, the first brick-and-mortar location of a popular food truck. Other businesses that have already opened on the block include Reveille Coffee, which has fast become a neighborhood gathering spot; Mizu Spa, a nail and massage spot; and Back to the Picture, a frame store.

And more are coming. One Mission Bay, the 350-unit condominium development opening later this year on Channel Street between Third and Fourth streets, has signed a lease for 3,600 square feet with Wine Merchant, the group that owns Ferry Plaza Wine Merchant in the Ferry Building and Oxbow Wine and Cheese Merchant in downtown Napa. Next door, fitness center LagreeFit 415, will open a 1,700-square-foot facility.

Terry Wachsner, a principal with the CIM Group, which is developing One Mission Bay, said the two businesses would debut in April, four months after the first residents move in. The condos are 65 percent sold. Eventually the building’s 16,000 square feet of retail will also include several more restaurants and possibly a bank.

“As more retail opens you are…