The CHEVI tethering complex: facilitating special deliveries.

VPS33B and VIPAR comprise the two known components of the recently christened class C Homologues in Endosome-Vesicle Interaction (CHEVI) complex, thought to act as a tethering complex in endosomal trafficking distinct from the HOPS and CORVET complexes in mammalian cells. A recent paper in The Journal of Pathology further explores the role of the CHEVI complex in the biogenesis of α-granules in megakaryocytes, identifying two novel interactors of this complex: α-tubulin and SEC22B, and demonstrating that VPS33B expression is required for the localization of SEC22B and the α-granule cargo VWF to proplatelets in megakaryocytes. These findings advance the current knowledge of the function of the CHEVI complex in α-granule biogenesis and together with studies in other systems, corroborate its role in the specialized delivery of cargo in different cell types.