Rab4 regulates recycling from early endosomes. We investigated the role of the rab4 effector rabaptin-5alpha and its putative partner gamma(1)-adaptin in membrane recycling. We found that rabaptin-5alpha forms a ternary complex with the gamma(1)-sigma(1) subcomplex of AP-1, via a direct interaction with the gamma(1)-subunit. The binding site for gamma(1)-adaptin is in the hinge region of rabaptin-5alpha, which is distinct from rab4- and rab5-binding domains. Endogenous or ectopically expressed gamma(1)- adaptin localized to both the trans-Golgi network and endosomes. Co-expressed rabaptin-5alpha and gamma(1)-adaptin, however, co-localized in a rab4-dependent manner on recycling endosomes. Transfection of rabaptin-5alpha caused enlarged endosomes and delayed recycling of transferrin. RNAi of rab4 had an opposing effect on transferrin recycling. Collectively, our data show that rab4-GTP acts as a scaffold for a rabaptin-5alpha- gamma(1)-adaptin complex on recycling endosomes and that interactions between rab4, rabaptin-5alpha and gamma(1)-adaptin regulate membrane recycling.
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http://dx.doi.org/10.1093/emboj/cdg257 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616.
The L-type Ca channel (Ca1.2) is essential for cardiac excitation-contraction coupling. To contribute to the inward Ca flux that drives Ca-induced-Ca-release, Ca1.
View Article and Find Full Text PDFJ Extracell Vesicles
January 2025
Vascular Biology Program, Boston Children's Hospital, Boston, Massachusetts, USA.
Extracellular vesicles (EVs) from brain-seeking breast cancer cells (Br-EVs) breach the blood-brain barrier (BBB) via transcytosis and promote brain metastasis. Here, we defined the mechanisms by which Br-EVs modulate brain endothelial cell (BEC) dynamics to facilitate their BBB transcytosis. BEC treated with Br-EVs show significant downregulation of Rab11fip2, known to promote vesicle recycling to the plasma membrane and significant upregulation of Rab11fip3 and Rab11fip5, which support structural stability of the endosomal compartment and facilitate vesicle recycling and transcytosis, respectively.
View Article and Find Full Text PDFFront Cell Dev Biol
January 2025
Department of Physiology, Immunology and Pathophysiology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.
Introduction: Cytomegalovirus (CMV) infection reorganizes early endosomes (EE), recycling endosome (RE), and trans-Golgi network (TGN) and expands their intermediates into a large perinuclear structure that forms the inner part of the cytoplasmic assembly complex (AC). The reorganization begins and results with the basic configuration (known as pre-AC) in the early (E) phase of infection, but the sequence of developmental steps is not yet well understood. One of the first signs of the establishment of the inner pre-AC, which can be observed by immunofluorescence, is the accumulation of Rab10.
View Article and Find Full Text PDFIndiana Univ J Undergrad Res
June 2024
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine.
Angiomotins (Amots) are a family of adaptor proteins with important roles in cell growth, migration, and proliferation. The Amot coiled-coil homology (ACCH) domain has a high affinity for non-phosphorylated and mono-phosphorylated phosphatidylinositol which provides specificity in the membrane association. The membrane specificity is linked with targeting and recycling of the membrane protein to maintain normal cell phenotypes and function.
View Article and Find Full Text PDFJ Environ Manage
January 2025
College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, China. Electronic address:
The treatment of landfill leachate using anaerobic membrane bioreactors (AnMBRs) often faces challenges such as poor removal efficiency, low methane yield and membrane fouling. This study applied AnMBRs with incrementally adding conductive materials to enhance the treatment of landfill leachate under high organic loading rates(35 kg COD/(m∙d)). With 50 g/L activated carbon, COD removal percentages and methane yield increased to 81.
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