Kinesin-1 regulates antigen cross-presentation through the scission of tubulations from early endosomes in dendritic cells.
Belabed M, Mauvais FX, Maschalidi S, Kurowska M, Goudin N, Huang JD, Fischer A, de Saint Basile G, van Endert P, Sepulveda FE, Ménasché G.
2020 Apr 14
Dendritic cells (DCs) constitute a specialized population of immune cells that present exogenous antigen (Ag) on major histocompatibility complex (MHC) class I molecules to initiate CD8 + T cell responses against pathogens and tumours. Although cross-presentation depends critically on the trafficking of Ag-containing intracellular vesicular compartments, the molecular machinery that regulates vesicular transport is incompletely understood. Here, we demonstrate that mice lacking Kif5b (the heavy chain of kinesin-1) in their DCs exhibit a major impairment in cross-presentation and thus a poor in vivo anti-tumour response. We find that kinesin-1 critically regulates antigen cross-presentation in DCs, by controlling Ag degradation, the endosomal pH, and MHC-I recycling. Mechanistically, kinesin-1 appears to regulate early endosome maturation by allowing the scission of endosomal tubulations. Our results highlight kinesin-1's role as a molecular checkpoint that modulates the balance between antigen degradation and cross-presentation.