Interleukin-15 (IL-15), a 114-amino acid cytokine related to IL-2, regulates immune homeostasis and the fate of many lymphocyte subsets. We reported that, in the blood of mice and humans, IL-15 is present as a heterodimer associated with soluble IL-15 receptor α (sIL-15Rα). Here, we show efficient production of this noncovalently linked but stable heterodimer in clonal human HEK293 cells and release of the processed IL-15·sIL-15Rα heterodimer in the medium. Purification of the IL-15 and sIL-15Rα polypeptides allowed identification of the proteolytic cleavage site of IL-15Rα and characterization of multiple glycosylation sites. Administration of the IL-15·sIL-15Rα heterodimer reconstituted from purified subunits resulted in sustained plasma IL-15 levels and in robust expansion of NK and T cells in mice, demonstrating pharmacokinetics and in vivo bioactivity superior to single chain IL-15. These identified properties of heterodimeric IL-15 provide a strong rationale for the evaluation of this molecule for clinical applications.
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http://dx.doi.org/10.1074/jbc.M113.461756 | DOI Listing |
J Med Chem
January 2025
Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Radiopharmaceutical theranostics holds significant promise in tumor diagnosis and treatment, but suboptimal tumor uptake and retention remain a persistent limitation. We have conjugated a unique albumin binder to our previously developed heterodimeric precursor HX01 and achieved a novel precursor L6, aiming to prolong circulation time and enhance tumor accumulation and retention. However, we observed that the NGR sequence of L6 was gradually rearranged to iso-DGR under alkaline conditions, resulting in decreased stability.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, Florida, USA; The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida, USA. Electronic address:
Synaptic adhesion molecules are essential components of the synapse, yet the diversity of these molecules and their associated functions remain to be fully characterized. Extracellular leucine rich repeat and fibronectin type III domain containing 1 (ELFN1) is a postsynaptic adhesion molecule in the brain that has been increasingly implicated in human neurological disease. ELFN1 is best known for trans-synaptically modulating group III metabotropic glutamate receptors (mGluRs).
View Article and Find Full Text PDFNat Commun
November 2024
Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China.
Background And Purpose: Metabotropic glutamate receptors (mGlus) are obligate dimer G protein coupled receptors that can all homodimerize and heterodimerize in select combinations. Responses of mGlu heterodimers to selective ligands, including orthosteric agonists and allosteric modulators, are largely unknown.
Experimental Approach: The pharmacological properties of each group II and III mGlu homodimer (except mGlu6) and several heterodimers were examined when stochastically assembled in HEK293T cells, or specifically measured using an improved G protein mediated BRET assay employing complimented fragments of NanoLuciferase.
Biochemistry (Mosc)
October 2024
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
Previously, we found that in the reaction center (RC) of the purple bacterium , formation of heterodimeric primary electron donor (P) caused by the substitution of His-L173 by Leu, was compensated by the second mutation Ile-L177 - His. Significant changes in the spectral properties, pigment composition, and redox potential of P observed in the H(L173)L RC, are restored to the corresponding characteristics of the native RC in the RC H(L173)L/I(L177)H, with the difference that the energy of the long-wavelength Q optical transition of P increases significantly (by ~75 meV). In this work, it was shown using light-induced difference FTIR spectroscopy that the homodimeric structure of P is preserved in the RC with double mutation with partially altered electronic properties: electronic coupling in the radical-cation of the P dimer is weakened and localization of the positive charge on one of its halves is increased.
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