Molecular mechanism to recruit galectin-3 into multivesicular bodies for polarized exosomal secretion.

ABSTRACT: The beta-galactoside binding lectin galectin-3 (Gal3) is found intracellularly and in the extracellular space. Secretion of this lectin is mediated independently of the secretory pathway by a not yet defined nonclassical mechanism. Here, we found Gal3 in the lumen of exosomes. Superresolution and electron microscopy studies visualized Gal3 recruitment and sorting into intraluminal vesicles. Exosomal Gal3 release depends on the endosomal sorting complex required for transport I (ESCRT-I) component Tsg101 and functional Vps4a. Either Tsg101 knockdown or expression of dominant-negative Vps4a^E228Q causes an intracellular Gal3 accumulation at multivesicular body formation sites. In addition, we identified a highly conserved tetrapeptide P(S/T)AP motif in the amino terminus of Gal3 th

SUBMITTER: Banfer S 

PROVIDER: S-EPMC5948969 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature