Avl9 defines a family of DENN domain GTPase-activating proteins.

Avl9, a DENN domain protein, acts as a GTPase-activating protein for Arf1, with conserved activity in humans and a role in cell migration.

• Why it matters: Understanding GTPase regulation is crucial for deciphering cellular signaling and trafficking pathways, yet many regulators remain unidentified, limiting insights into cell function and disease mechanisms.
• What they did: The study used computational interaction screens and functional assays to identify Avl9 as an Arf1 GAP, demonstrating its recruitment to secretory vesicles via Rab8 and its conserved activity in humans.
• The result: This work reveals a new family of DENN GAP proteins that modulate key cellular processes, including secretion and migration, and explains the role of DENND6A in lysosome positioning through Arf-GAP activity.