The assembly of clathrin into baskets or cages in vitro may depend on formation of complex between clathrin and a polypeptide doublet migrating in the 30000-mol.wt. region. Clathrin with several associated proteins was isolated from coated-vesicle fractions of bovine cerebral cortex. Most associated proteins were separated by Sepharose 4B column chromatograhy. The eluted clathrin retained only the 30000-mol.wt. doublet and assembled into baskets at pH 6.5. Limited proteolysis of coated vesicles or clathrin assembled as baskets removed these clathrin-associated proteins (CAPs) without detectably altering clathrin. Enzyme-treated clathrin assembled into open-lattice structures but no longer formed baskets in vitro. Latex particles with bound enzyme cleaved the CAPs from coated vesicles and clathrin baskets, suggesting that the CAPs protrude from the exterior of the clathrin lattice.
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http://dx.doi.org/10.1042/bj2010297 | DOI Listing |
Elife
January 2025
Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.
The steroid hormone progesterone (P4) regulates multiple aspects of reproductive and metabolic physiology. Classical P4 signaling operates through nuclear receptors that regulate transcription. In addition, P4 signals through membrane P4 receptors (mPRs) in a rapid nongenomic modality.
View Article and Find Full Text PDFFront Immunol
January 2025
IrsiCaixa, Badalona, Spain.
Introduction: HIV-1 exploits dendritic cells (DCs) to spread throughout the body via specific recognition of gangliosides present on the viral envelope by the CD169/Siglec-1 membrane receptor. This interaction triggers the internalization of HIV-1 within a structure known as the sac-like compartment. While the mechanism underlying sac-like compartment formation remains elusive, prior research indicates that the process is clathrin-independent and cell membrane cholesterol-dependent and involves transient disruption of cortical actin.
View Article and Find Full Text PDFJ Cell Sci
January 2025
Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
Here, we apply SuperResNET network analysis of dSTORM single-molecule localization microscopy (SMLM) to determine how the clathrin endocytosis inhibitors pitstop 2, dynasore and Latrunculin A alter the morphology of clathrin-coated pits. SuperResNET analysis of HeLa and Cos7 cells identifies: small oligomers (Class I); pits and vesicles (Class II); and larger clusters corresponding to fused pits or clathrin plaques (Class III). Pitstop 2 and dynasore induce distinct homogeneous populations of Class II structures in HeLa cells suggesting that they arrest endocytosis at different stages.
View Article and Find Full Text PDFInt 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.
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