Clathrin-associated proteins were separated from clathrin under various clathrin-denaturing conditions, i.e. heating, freezing and isoelectric precipitation. The proteins retained biological activity; they were purified further by affinity chromatography on calmodulin-conjugated CNBr-Sepharose 4B and used for antibody purification. The affinity-purified anti-(clathrin-associated proteins) antibodies gave a fluorescent dotted pattern in cultured fibroblasts consistent with the known distribution of clathrin. Chemical cross-linking of pure clathrin-associated proteins indicated that these polypeptides exist as monomers in solution, each possessing Ca2+-dependent affinity for calmodulin to which they bind in a 1:1 molar ratio. Chymotryptic treatment of coated vesicles selectively cleaved the clathrin-associated proteins into a 15 000-18 000-Mr doublet polypeptide. These subfragments retained their Ca2+-dependent affinity for calmodulin. Our results support a regulatory role for clathrin-associated proteins in clathrin assemblies.
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Int J Mol Sci
January 2025
Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital/CSIC/University of Seville, 41013 Seville, Spain.
The ubiquitin proteasome system (UPS) is implicated in protein homeostasis. One of the proteins involved in this system is HERC1 E3 ubiquitin ligase, which was associated with several processes including the normal development and neurotransmission at the neuromuscular junction (NMJ), autophagy in projection neurons, myelination of the peripheral nervous system, among others. The tambaleante (tbl) mouse model carries the spontaneous mutation Gly483Glu substitution in the HERC1 E3 protein.
View Article and Find Full Text PDFCell Mol Life Sci
January 2025
School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
C1orf115 has been identified in high-throughput screens as a regulator of multidrug resistance possibly mediated through an interaction with ATP-dependent membrane transporter ABCB1. Here we show that C1orf115 not only shares structural similarities with FACI/C11orf86 to interact with clathrin adaptors to undergo endocytosis, but also induces ABCA1 transcription to promote cholesterol efflux. C1orf115 consists of an N-terminal intrinsically disordered region and a C-terminal α-helix.
View Article and Find Full Text PDFPhysiol Plant
January 2025
Department of Plant Molecular Biology, Biophore Building, University of Lausanne, Lausanne, Switzerland.
Understanding the role and mode of action of nutrient transporters requires information about their dynamic associations with plant membranes. Historically, apoplastic nutrient export has been associated with proteins localized at the plasma membrane (PM), while the role of endomembrane localization has been less explored. However, recent work on the PHOSPHATE 1 (PHO1) inorganic phosphate (Pi) exporter demonstrated that, although primarily localized at the Golgi and trans-Golgi network (TGN) vesicles, PHO1 does associate with the PM when clathrin-mediated endocytosis (CME) was inhibited, supporting a mechanism for Pi homeostasis involving exocytosis.
View Article and Find Full Text PDFBrief Bioinform
November 2024
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China.
Clathrin proteins, key elements of the vesicle coat, play a crucial role in various cellular processes, including neural function, signal transduction, and endocytosis. Disruptions in clathrin protein functions have been associated with a wide range of diseases, such as Alzheimer's, neurodegeneration, viral infection, and cancer. Therefore, correctly identifying clathrin protein functions is critical to unravel the mechanism of these fatal diseases and designing drug targets.
View Article and Find Full Text PDFAdv Protein Chem Struct Biol
January 2025
Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences Hospital (NIMHANS), Institute of National Importance, Bangalore, Karnataka, India.
Lipids play an essential role in synaptic function, significantly impacting synaptic physiology through their dynamic nature and signaling capabilities. Membrane lipids, including cholesterol, phospholipids, and gangliosides, are crucial for synaptic organization and function. They act as structural integrators and signaling molecules, guiding vesicle intracellular movement and regulating enzyme activity to support neuronal activity.
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