Liu D, Qian D, Shen H, Gong D. Structure of the human Meckel-Gruber protein Meckelin.
SCIENCE ADVANCES 2021;
7:eabj9748. [PMID:
34731008 PMCID:
PMC8565905 DOI:
10.1126/sciadv.abj9748]
[Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Mutations in the Meckelin gene account for most cases of the Meckel-Gruber syndrome, the most severe ciliopathy with a 100% mortality rate. Here, we report a 3.3-Å cryo–electron microscopy structure of human Meckelin (also known as TMEM67 and MKS3). The structure reveals a unique protein fold consisting of an unusual cysteine-rich domain that folds as an arch bridge stabilized by 11 pairs of disulfide bonds, a previously uncharacterized domain named β sheet–rich domain, a previously unidentified seven-transmembrane fold wherein TM4 to TM6 are broken near the cytoplasmic surface of the membrane, and a coiled-coil domain placed below the transmembrane domain. Meckelin forms a stable homodimer with an extensive dimer interface. Our structure establishes a framework for dissecting the function and disease mechanisms of Meckelin.
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