Report

Structural insights into immunoglobulin M

See allHide authors and affiliations

Science  06 Feb 2020:
eaaz5425
DOI: 10.1126/science.aaz5425

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Abstract

Immunoglobulin M (IgM) plays a pivotal role in both humoral and mucosal immunity. Its assembly and transport depend on the joining chain (J-chain) and the polymeric immunoglobulin receptor (pIgR), but the underlying molecular mechanisms of these processes are unclear. Here we report a cryo-electron microscopy structure of the Fc region of human IgM in complex with the J-chain and pIgR ectodomain. The IgM-Fc pentamer is formed asymmetrically, resembling a hexagon with a missing triangle. The tailpieces of IgM-Fc pack into an amyloid-like structure to stabilize the pentamer. The J-chain caps the tailpiece assembly and bridges the interaction between IgM-Fc and pIgR, which undergoes a large conformational change to engage the IgM–J complex. These results provide a structural basis for the function of IgM.

View Full Text

Stay Connected to Science