Structure of a TRAPPII-Rab11 activation intermediate reveals GTPase substrate selection mechanisms

Bagde, Saket R.; Fromme, J. Christopher

doi:10.1126/sciadv.abn7446

Cited by 17 publications

(50 citation statements)

References 56 publications

(104 reference statements)

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“…If the N-terminal domain of Mon1 in an autoinhibited state would prevent binding of the HVD, Rab7 may not get efficient access to the active site. Such a control of Rab access to the active site would be in part reminiscent of the gating mechanism of the TRAPP complexes (Thomas et al, 2019;Bagde and Fromme, 2022). These complexes share the same active site, but have distinct subunits in TRAPPIII and TRAPPII, which determine specificity.…”

Section: Discussionmentioning

confidence: 99%

Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation

Borchers

Janz

Schäfer

et al. 2023

Preprint

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Maturation from early to late endosomes depends on the exchange of their marker proteins Rab5 to Rab7. This requires Rab7 activation by its specific guanine nucleotide exchange factor (GEF) Mon1-Ccz1. Efficient GEF activity of this complex on membranes depends on Rab5, thus driving Rab-exchange on endosomes. However, molecular details on the role of Rab5 in Mon1-Ccz1 activation are unclear. Here we identify key features in Mon1 involved in GEF regulation. We show that the intrinsically disordered N-terminal domain of Mon1 autoinhibits Rab5-dependent GEF-activity on membranes. Consequently, Mon1 truncations result in higher GEF activityin vitro, and a shift from Rab5 to more Rab7 positive structures inDrosophilanephrocytes and yeast, suggesting faster endosomal maturation. Using modeling, we further identify a conserved Rab5 binding site in Mon1. Mutations impairing Rab5 interaction result in poor GEF activity on membranes and growth defectsin vivo. Our analysis provides a framework to understand the mechanism of Rab-conversion and organelle maturation along the endomembrane system.SummaryTransport of proteins via the endolysosomal pathway requires Rab5 on early endosomes, which is replaced by Rab7 on late endosomes. Here, we identify distinct regulatory sites in the Rab7 activator, the Mon1-Ccz1 complex, shedding light on the regulation of Rab5 to Rab7 transition.

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Section: Discussionmentioning

confidence: 99%

Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation

Borchers

Janz

Schäfer

et al. 2023

Preprint

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“…(B) Cryo‐EM structure of the budding yeast TRAPPIII complex bound to Rab1/Ypt1 [54]. (C) Cryo‐EM structure of the budding yeast TRAPPII complex bound to Rab11/Ypt32 [60]. Figure modified from Ref [60].…”

Section: Figmentioning

confidence: 99%

The TRAPP complexes: discriminating GTPases in context

Bagde

Fromme

2022

FEBS Letters

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Correct localization of Rab GTPases in cells is critical for proper function in membrane trafficking. Guanine‐nucleotide exchange factors (GEFs) act as the primary determinants of Rab localization by activating and stabilizing their Rab substrates on specific organelle and vesicle membranes. The TRAPP complexes TRAPPII and TRAPPIII are two related GEFs that use the same catalytic site to activate distinct Rabs, Rab11 and Rab1, respectively. The Rab C‐terminal hypervariable domain (HVD) is an important specificity determinant for the budding yeast TRAPP complexes, with the length of the HVD playing a critical role in counter‐selection. Several recent studies have used cryo‐EM to illuminate how the yeast and metazoan TRAPP complexes identify and activate their substrates. This review summarizes recently characterized Rab substrate selection mechanisms and highlights how the membrane surface provides critical context for the GEF‐GTPase interactions.

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“…The TRAPPC2L A2G variant is indeed pathogenic. As the importance of Rab proteins was already discussed as it pertains to the GA, the structure of an activation intermediate TRAP-PII-Rab11 (Figure 4) divulged a GTPase substrate selection mechanism [31]. Another GA protein family that transports copper P-type ATPases, ATP7A and B that are trafficked by AP1S1 which causes MEDNIK syndrome that the trans-Golgi and endosomes match cargo molecules including neurotransmitters to their carriers.…”

Section: Golgipathies: Early Secretory Pathway Defects and Ndds With ...mentioning

confidence: 99%

“…Cryo-EM structure TRAPPII-Rab11/Ypt32 complex. Complex in closed state is an activation intermediate discovered to be GTPase substrate mechanism (EMDB-26228)[31]…”

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confidence: 99%

Pioneering Organelle Structural Biology: Golgi Apparatus Dysfunction in Parkinson’s Disease, Neurodevelopmental Disorders, and Cancer

Gómez¹

2022

Preprint

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The Golgi apparatus (GA) dysfunctions in Parkinson’s Disease (PD), neurodevelopmental disorders (NDDs), cancer, and organelle structural biology (OSB) can provide insights into therapeutic targets, gene therapy, and drug design. Primary defects and fragmentation within the GA are implicated in a wide range of neurodegenerative diseases. GA defects typically result in mislocation of proteins, accumulation of undegraded proteins, and impaired glycosylation of proteins. Inhibition of vesicular trafficking by α-synuclein (aSyn) may affect the dopamine-producing neurons and neuromodulators. GA regulates apoptosis during pathological mechanisms of neurological diseases and could provide new avenues in treatments through translation research. PD patients bearing the hereditary E46K disease mutation manifest the clinical picture of parkinsonism. How do we provide high resolution nanoimages of the GA during disease to capture dysfunction? Could we visualize the aSyn traffic jam between vesicles in the organelles ER and GA? OSB is emerging as a field as more technology advances and is more accessible. Structural studies of the GA will advance the field of neurological disease forward with an in depth understanding of dysfunction, fragmentation, and defects. Discoveries of the GA in PD, NDDs, and cancer would break new ground and provide translational medicine data of these diseases. Future research could be visualizing high angle annular dark field-STEM (HAADF-STEM) tomograms, cryogenic electron tomography (cryo-ET), multiplex correlative light and electron microscopy (cryo-CLEM), nanobody-assisted tissue immunostaining for volumetric EM (NATIVE) and using soft X-ray tomography (SXT) and computational reconstruction of the GA.

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Structure of a TRAPPII-Rab11 activation intermediate reveals GTPase substrate selection mechanisms

Cited by 17 publications

References 56 publications

Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation

Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation

The TRAPP complexes: discriminating GTPases in context

Pioneering Organelle Structural Biology: Golgi Apparatus Dysfunction in Parkinson’s Disease, Neurodevelopmental Disorders, and Cancer

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