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Crystal structure of human Rab11-Rabin8-FIP3
Structural highlights
FunctionRB11A_HUMAN The small GTPases Rab are key regulators of intracellular membrane trafficking, from the formation of transport vesicles to their fusion with membranes. Rabs cycle between an inactive GDP-bound form and an active GTP-bound form that is able to recruit to membranes different set of downstream effectors directly responsible for vesicle formation, movement, tethering and fusion. That Rab regulates endocytic recycling. Acts as a major regulator of membrane delivery during cytokinesis. Together with MYO5B and RAB8A participates in epithelial cell polarization. Together with RAB3IP, RAB8A, the exocyst complex, PARD3, PRKCI, ANXA2, CDC42 and DNMBP promotes transcytosis of PODXL to the apical membrane initiation sites (AMIS), apical surface formation and lumenogenesis. Together with MYO5B participates in CFTR trafficking to the plasma membrane and TF (Transferrin) recycling in nonpolarized cells. Required in a complex with MYO5B and RAB11FIP2 for the transport of NPC1L1 to the plasma membrane. Participates in the sorting and basolateral transport of CDH1 from the Golgi apparatus to the plasma membrane. Regulates the recycling of FCGRT (receptor of Fc region of monomeric Ig G) to basolateral membranes. May also play a role in melanosome transport and release from melanocytes.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedThe small GTPase Rab11 and its effectors FIP3 and Rabin8 are essential to membrane-trafficking pathways required for cytokinesis and ciliogenesis. Although effector binding is generally assumed to be sequential and mutually exclusive, we show that Rab11 can simultaneously bind FIP3 and Rabin8. We determined crystal structures of human Rab11-GMPPNP-Rabin8 and Rab11-GMPPNP-FIP3-Rabin8. The structures reveal that the C-terminal domain of Rabin8 adopts a previously undescribed fold that interacts with Rab11 at an unusual effector-binding site neighboring the canonical FIP3-binding site. We show that Rab11-GMPPNP-FIP3-Rabin8 is more stable than Rab11-GMPPNP-Rabin8, owing to direct interaction between Rabin8 and FIP3 within the dual effector-bound complex. The data allow us to propose a model for how membrane-targeting complexes assemble at the trans-Golgi network and recycling endosomes, through multiple weak interactions that create high-avidity complexes. Structure of Rab11-FIP3-Rabin8 reveals simultaneous binding of FIP3 and Rabin8 effectors to Rab11.,Vetter M, Stehle R, Basquin C, Lorentzen E Nat Struct Mol Biol. 2015 Aug 10. doi: 10.1038/nsmb.3065. PMID:26258637[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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