Enables solute:sodium symporter activity. Involved in transmembrane transport. Is active in plasma membrane. Is expressed in adult head; adult main segment of Malpighian tubule; ensheathing glial cell; larval ventral nerve cord; and lateral cord neurons. Human ortholog(s) of this gene implicated in congenital hypothyroidism and thyroid dyshormonogenesis 1. Orthologous to human SLC5A12 (solute carrier family 5 member 12); SLC5A5 (solute carrier family 5 member 5); and SLC5A8 (solute carrier family 5 member 8).