Structural insights into GM4951 as a lipid droplet GTPase regulating hepatic lipid metabolism.

ABSTRACT: GM4951 is an immunity-related GTPase (IRG) that counteracts hepatic lipid accumulation in mice fed a high-fat diet. We determine full-length protein structures of GTPγS- and GDP-bound GM4951, and two missense mutants (N86K or D125G) associated with metabolic dysfunction-associated steatotic liver disease (MASLD) in mice. All four structures reveal a conserved GTPase domain fold and a helix bundle composed of the N- and C-terminal regions. Each mutation alters the dynamics of the switch-I and switch-II loops important for catalytic function and lipid droplet (LD) localization. GM4951 predominantly forms dimers in vitro. Cryo-electron microscopy reveals a dimer interface formed by the helical domains of two protomers (tail to tail), distinct from other IRGs. The N-terminal helices are necess

SUBMITTER: Raj R 

PROVIDER: S-EPMC12749288 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature