LEWISTON — A Lewiston-Auburn-based charter school is a possible proposal to fill one of the last four available charter school slots in Maine.

All of ME Academy, a kindergarten through fifth-grade school, was one of six proposals, including a virtual school that has applied the last three years, outlined in letters of intent sent to the Maine Charter School Commission by Wednesday’s deadline.

Maine charter schools are publicly funded but operate independently of public school districts. By law, the state has a cap of 10 charter schools until 2021.

Five charter schools are in operation. A sixth charter school, Maine Connections Academy, plans to open in the fall and will be the state’s first virtual charter school, with students learning largely from home and getting lessons online.

Some of the other applicants want to open schools in the York County; Kennebunk and Sidney.