Lipid packing defects and membrane charge control RAB GTPase recruitment

• Published in: Traffic (Copenhagen, Denmark) Vol. 19; no. 7; pp. 536 - 545
• Main Authors: Kulakowski, Guillaume, Bousquet, Hugo, Manneville, Jean‐Baptiste, Bassereau, Patricia, Goud, Bruno, Oesterlin, Lena K.
• Format: Journal Article
• Language: English
• Published: Former Munksgaard John Wiley & Sons A/S 01.07.2018; Wiley Subscription Services, Inc; Wiley
• Subjects: Biochemistry, Molecular Biology; curvature sensing; Defects; Electrostatic properties; geranylgeranyl; Guanosine triphosphatases; Humans; Hydrophobicity; Intracellular; Life Sciences; lipid packing defects; Lipids; Localization; Membrane Lipids - chemistry; Membrane Lipids - metabolism; membrane order; Original; Packing; Physicochemical properties; prenylation; Protein Binding; Protein Prenylation; Proteins; rab GTP-Binding Proteins - chemistry; rab GTP-Binding Proteins - metabolism; Static Electricity; Unilamellar Liposomes - chemistry; Unilamellar Liposomes - metabolism; prenylation; curvature sensing; lipid packing defects; membrane order; geranylgeranyl
• ISSN: 1398-9219; 1600-0854
• DOI: 10.1111/tra.12568

Specific intracellular localization of RAB GTPases has been reported to be dependent on protein factors, but the contribution of the membrane physicochemical properties to this process has been poorly described. Here, we show that three RAB proteins (RAB1/RAB5/RAB6) preferentially bind in vitro to disordered and curved membranes, and that this feature is uniquely dependent on their prenyl group. Our results imply that the addition of a prenyl group confers to RAB proteins, and most probably also to other prenylated proteins, the ability to sense lipid packing defects induced by unsaturated conical‐shaped lipids and curvature. Consistently, RAB recruitment increases with the amount of lipid packing defects, further indicating that these defects drive RAB membrane targeting. Membrane binding of RAB35 is also modulated by lipid packing defects but primarily dependent on negatively charged lipids. Our results suggest that a balance between hydrophobic insertion of the prenyl group into lipid packing defects and electrostatic interactions of the RAB C‐terminal region with charged membranes tunes the specific intracellular localization of RAB proteins. Vesicular trafficking between intracellular compartments is regulated by many proteins such as RAB GTPases. Deciphering the molecular mechanisms governing RAB localization is thus critical to understand intracellular transport. We focused our study on the role of the physicochemical properties of membranes in the specific recruitment of RAB proteins. Using in vitro reconstitution, we demonstrate that a balance between electrostatic interactions and hydrophobic insertion of the RAB C‐terminal prenyl group into lipid packing defects controls the recruitment of RAB proteins.