Biology subjects

Dansercoer, A.

Publications and source records attributed to Dansercoer, A..

2 recordsLinked to original sources

bioRxiv2023

Ym1 protein crystals promote type 2 immunity

Spontaneous protein crystallization is a rare event, yet protein crystals are frequently found in eosinophil-rich inflammation. In humans, Charcot-Leyden crystals (CLCs) are made from galectin-10 (Gal10) protein, an abundant protein in eosinophils. Whereas mice do not encode Gal10 in their genome, they do form pseudo-CLCs, made from the chitinase-like proteins Ym1 and/or Ym2, encoded by Chil3 and Chil4 and made by myeloid and epithelial cells respectively. Here, we investigated the biological effects of pseudo-CLCs since their function is currently unknown. We produced recombinant Ym1 crystals which were shown to have identical crystal packing and structure by X-ray crystallography as in vivo native crystals derived from murine lung. When administered to the airways of mice, crystalline but not soluble Ym1 stimulated innate and adaptive immunity and acted as a type 2 immune adjuvant for eosinophilic inflammation via triggering of dendritic cells (DCs). Murine Ym1 protein crystals found at sites of eosinophilic inflammation reinforce type 2 immunity and could serve as a surrogate model for studying the biology of human CLCs.

immunology↗

bioRxiv2022

Mechanism of receptor assembly via the pleiotropic adipokine Leptin

The adipokine Leptin activates its type I cytokine receptor (LEP-R) in the hypothalamus to regulate body weight and exerts additional pleiotropic functions in immunity, fertility, and cancer. However, the structure and mechanism of Leptin-mediated LEP-R assemblies has remained unclear. Here, we show that Leptin:LEP-R assemblies adopt an unprecedented structure within the type I cytokine receptor family featuring 3:3 stoichiometry. We validate Leptin-induced trimerization of LEP-R in the plasma membrane of living cells via multicolor single molecule microscopy. In mediating such assemblies Leptin undergoes drastic restructuring that activates its site III for binding to the Ig-domain of an adjacent LEP-R molecule in the complex. These interactions are abolished by pathological mutations linked to obesity. Collectively, our study uncovers an evolutionarily conserved Leptin:LEP-R assembly as a new mechanistic blueprint for Leptin-mediated signaling in physiology and disease, including insights into how the lowly abundant signaling-competent isoforms of LEP-R can productively participate in signaling.

molecular biology↗