| 2010 |
The dimeric Mon1-Ccz1 complex is the guanine nucleotide exchange factor (GEF) for the late endosomal Rab7 homolog Ypt7. The complex, but neither protein alone, counteracts GAP function in vivo, rescues in vitro fusion of vacuoles carrying Ypt7-GDP, and promotes nucleotide exchange on Ypt7 independently of Vps39/HOPS. |
In vitro nucleotide exchange assay, in vitro vacuole fusion assay, in vivo GAP suppression assay |
Current biology : CB |
High |
20797862
|
| 2002 |
Mon1 and Ccz1 physically interact as a stable protein complex (the Ccz1-Mon1 complex), function in nearly all membrane-trafficking pathways targeting the vacuole, and act after transport vesicle formation but before or at the fusion step with the vacuole. The complex peripherally associates with a perivacuolar compartment. |
Co-immunoprecipitation, subcellular fractionation, fluorescence microscopy, genetic deletion analysis with multiple pathway readouts (Cvt, autophagy, pexophagy, CPY/ALP/MVB pathways) |
The Journal of biological chemistry |
High |
12364329
|
| 2003 |
The Ccz1-Mon1 complex is required for the tethering/docking stage of homotypic vacuole fusion. In its absence, SNARE pairing integrity and the class C Vps/HOPS complex interaction with unpaired SNAREs are both impaired. The complex co-localizes with other fusion components on the vacuole as part of the cis-SNARE complex, and its vacuolar association is regulated by the class C Vps/HOPS complex. |
In vitro homotypic vacuole fusion assay, SNARE co-immunoprecipitation, fluorescence co-localization, genetic analysis |
The Journal of cell biology |
High |
14662743
|
| 2001 |
Ccz1 physically interacts with the Rab GTPase Ypt7. Extragenic suppressors of CCZ1 deletion all mapped to mutated alleles of YPT7 (with mutations in the guanine-binding domains), and direct physical interaction was confirmed by co-immunoprecipitation. |
Suppressor genetics, co-immunoprecipitation |
Journal of cell science |
Medium |
11590240
|
| 2014 |
Mon1-Ccz1 is recruited to endosomes and vacuoles through binding to phosphatidylinositol 3-phosphate (PI3P). After activating Ypt7, Mon1 is phosphorylated by the type 1 casein kinase Yck3 and released from vacuoles for recycling. Phosphorylation-site mutants of Mon1 are retained on vacuoles, and this retention is rescued by addition of recombinant Yck3. |
Lipid competition assay (PI3P), recombinant kinase add-back assay, phosphomutant analysis, vacuole membrane binding assay |
Molecular biology of the cell |
High |
24623720
|
| 2018 |
Mon1-Ccz1 is specifically recruited to the pre-autophagosomal structure under starvation by directly binding Atg8 (yeast LC3 homolog) via at least one LIR motif in the Ccz1 C-terminus. This LIR motif is essential for autophagy but not for endosomal transport. Only wild-type, not LIR-mutated Mon1-Ccz1, promotes Atg8-dependent activation of Ypt7. |
LIR motif mutagenesis, in vitro binding assay, GEF activity assay, fluorescence microscopy, yeast genetics |
eLife |
High |
29446751
|
| 2016 |
The Ccz1-Mon1-Rab7 module is required for autophagosome-lysosome fusion in Drosophila fat cells. Rab5 is dispensable for the Ccz1-Mon1-dependent recruitment of Rab7 to PI3P-positive autophagosomes (which are generated by Atg14-containing Vps34 PI3 kinase complex), placing the Ccz1-Mon1 complex downstream of PI3P generation and upstream of autophagosome-lysosome fusion. |
Genetic loss-of-function (Drosophila mutants), fluorescence microscopy, autophagosome quantification, epistasis analysis |
Molecular biology of the cell |
Medium |
27559127
|
| 2015 |
Mon1-Ccz1 activates Rab7 specifically on late endosomes in mammalian cells; Rab7 activity on lysosomes is independent of Mon1-Ccz1. Mon1-Ccz1 dissociates from lysosomes after late endosome-lysosome fusion. Active Rab7 on lysosomes (independent of Mon1-Ccz1) plays a role in perinuclear lysosome clustering. |
FRET-based Rab7 activity sensor, confocal FRET imaging, siRNA knockdown of Mon1-Ccz1, EGF-induced macropinocytosis assay |
Journal of cell science |
Medium |
26627821
|
| 2017 |
C18orf8/RMC1 is a new subunit of the CCZ1-MON1 RAB7 guanine exchange factor complex and positively regulates RAB7 recruitment to late endosomes/autophagosomes. This was identified through interaction proteomics of proteins accumulating in GABARAP/L1/L2-deficient cells. |
Interaction proteomics (AP-MS), genetic cell engineering (ATG8 knockouts), quantitative autophagosome proteomics |
Molecular and cellular biology |
Medium |
29038162
|
| 2021 |
C5orf51 is a component of the MON1-CCZ1 complex, identified as an interactor of GDP-locked RAB7A by proximity biotinylation. In the absence of C5orf51, RAB7A localization on depolarized mitochondria is compromised and RAB7A is degraded by the proteasome, indicating C5orf51 stabilizes RAB7A and supports its mitochondrial recruitment during mitophagy. |
Proximity-dependent biotinylation (miniTurbo), co-immunoprecipitation, knockout cell analysis, fluorescence microscopy |
Autophagy |
Medium |
34432599
|
| 2022 |
The lysosomal V-ATPase a3 subunit interacts with the Mon1A-Ccz1 complex (GEF for Rab7) via the amino-terminal half domain of a3 and the longin motifs of Mon1A and Ccz1. This interaction is required for Mon1A-Ccz1 localization to secretory lysosomes in osteoclasts, which mediates Rab7 recruitment to the organelle. |
Co-immunoprecipitation in HEK293T cells, domain mapping by truncation mutants, endogenous Ccz1 localization analysis in a3-knockout osteoclasts |
Scientific reports |
Medium |
35589873
|
| 2023 |
Cryo-EM structure of the metazoan Mon1-Ccz1-Bulli (MCBulli) complex was solved at 3.2 Å resolution. Bulli associates as a leg-like extension at the periphery of the Mon1-Ccz1 heterodimer and does not impact GEF activity or interactions with recruiter/substrate GTPases, but likely serves as a recruitment platform for additional regulators of endolysosomal trafficking. |
Cryo-electron microscopy (3.2 Å), structural analysis |
Proceedings of the National Academy of Sciences of the United States of America |
High |
37155863
|
| 2023 |
An amphipathic helix in Ccz1 is required for Mon1-Ccz1 function in autophagy but not endosomal maturation, revealing a mechanism for differential targeting to autophagosomes vs. endosomes. The Ccz1 amphipathic helix interacts with lipid packing defects, Mon1 basic patches bind positively charged lipids, and association with recruiter proteins synergistically governs membrane recruitment. Interaction with recruiter proteins can further stimulate GEF activity beyond membrane concentration effects. |
Mutagenesis, lipid-binding assays, in vitro GEF activity assays, yeast functional genetics |
The Journal of biological chemistry |
High |
36649906
|
| 2023 |
CCZ1 controls early-to-late endosomal trafficking of Marburg and Ebola filoviruses, functioning as an essential host factor in the early stage of filovirus replication. Loss of CCZ1 nearly completely abolishes Marburg and Ebola infections, validated in 3D primary human hepatocyte cultures and blood-vessel organoids. |
Haploid cell genetic screen, CCZ1 knockout validation, 3D primary human tissue models (hepatocyte cultures, blood-vessel organoids), viral infection assays |
Nature communications |
Medium |
37880247
|
| 2022 |
CCZ1-MON1A complex dysfunction causes decreased active RAB7 on autophagosome fractions in Alzheimer's disease models. Overexpressing CCZ1-MON1A increases active RAB7, enhances autophagosome maturation, and promotes degradation of APP-CTFs, Aβ, and P-tau in an autophagy-dependent manner. |
Autophagosome fractionation, GST-R7BD affinity isolation assay for GTP-RAB7, AAV-mediated overexpression in mouse brain, immunoblotting |
Theranostics |
Medium |
35198070
|
| 2025 |
Structural and biochemical comparison of Mon1-Ccz1 and Fuzzy-Inturned reveals that both tri-longin domain GEF complexes use a conserved sequence motif of their substrate GTPases for catalysis, while secondary interactions mediate target discrimination. The metazoan RMC1/Bulli subunit mediates membrane recruitment of the Mon1-Ccz1 GEF complex via electrostatic interactions through a distinct interface from the fungal dimer, demonstrated by protein-lipid interaction studies and functional characterization in flies. |
Structural determination, protein-lipid interaction assays, in vitro reconstitution, functional genetics in Drosophila |
Science advances |
High |
40864718
|
| 2010 |
In C. elegans, CCZ-1 mediates digestion of apoptotic corpses by acting in phagosome maturation through recruitment of the GTPase RAB-7 to phagosomes, placing CCZ-1 upstream of RAB-7 in the phagosome maturation pathway. |
Genetic loss-of-function (C. elegans deletion mutants), fluorescence microscopy of corpse persistence and RAB-7 recruitment |
Journal of cell science |
Medium |
20519582
|
| 2014 |
In C. elegans, CCZ-1 functions independently of SAND-1 (Mon1 ortholog) in gut granule (lysosome-related organelle) biogenesis, possibly acting with GLO-3 as a GEF for the Rab32/38-related GTPase GLO-1. Point mutations in GLO-1 predicted to increase spontaneous nucleotide exchange suppress loss of gut granules by ccz-1 mutants, genetically placing CCZ-1 upstream of GLO-1. |
Genetic epistasis (suppressor analysis), fluorescence microscopy, C. elegans mutant analysis |
Molecular biology of the cell |
Low |
24501423
|
| 2026 |
The trimeric Bulli-Mon1-Ccz1 Rab7 GEF complex (BuMC1-GEF) interacts with Rab5, which stimulates its GEF activity during endosomal maturation in Drosophila nephrocytes. GAPsec is identified as a GAP for Rab5 required for endosomal maturation; its inactivation results in enlarged dysfunctional endosomes unable to fuse with lysosomes. |
Drosophila genetic loss-of-function, fluorescence microscopy of endosomal trafficking, biochemical interaction analysis |
Journal of cell science |
Medium |
41943871
|