Biologists at Brown University have discovered a new signaling molecule in flies that helps explain how cells send many long-haul tissue-building messages, as well as provides new clues to how human development goes awry. In humans, a key family of signaling molecules are bone morphogenic proteins (BMPs). In fruit flies, the analogous proteins are called ‘glass-bottom boat’ (Gbb). The researchers found that Gbb38 is responsible for more signaling activity in tissues where it is abundant than Gbb15, previously believed to be the source of signaling. They also found that a mutation that interrupts Gbb38 production in flies, is analogous to the mutations associated with developmental disorders in different tissues in people. “If large forms of human BMPs are indeed present... then they could be a very useful alternatives to the short BMPs because the large forms are more active in terms of signaling and have different properties in vivo,” Kristi Wharton, who studied the proteins, said.