Animals must maintain proper balance between energy intake and expenditure. Recently, we descovered the enzymaticco-factor tetrahydrobiopterin (BH4) inhibits feeding in Drosophila. BH4 biosynthesis requires the sequential action of theconserved enzymes Punch, Purple, and Sepiapterin Reductase (Sptr). Although we observe increased feeding upon lossof Punch and Purple in the adult fat body, loss of Sptr must occur in the brain. We found Sptr expression is requiredin four adult brain neurons that express NPF, the fly homologue of the vertebrate appetite regulator NPY. Mechanistically,we found BH4 deficiency reduces NPF levels, while excess BH4 increases NPF accumulation without altering its expression.

• Do-Hyoung Kim(School of Life Sciences, Gwangju Institute of Science and Technology (GIST))
• Minjung Shin(Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST))
• Sung-Hwan Jung(School of Life Sciences, Gwangju Institute of Science and Technology (GIST))
• Young-Joon Kim(School of Life Sciences, Gwangju Institute of Science and Technology (GIST))
• Walton D. Jones(Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST))