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Proc Natl Acad Sci U S A. 2018 Sep 4;115(36):8984-8989. doi: 10.1073/pnas.1810291115. Epub 2018 Aug 20.

Recycling of Golgi glycosyltransferases requires direct binding to coatomer.

Author information

1
Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110.
2
Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110 skornfel@wustl.edu.

Abstract

The glycosyltransferases of the mammalian Golgi complex must recycle between the stacked cisternae of that organelle to maintain their proper steady-state localization. This trafficking is mediated by COPI-coated vesicles, but how the glycosyltransferases are incorporated into these transport vesicles is poorly understood. Here we show that the N-terminal cytoplasmic tails (N-tails) of a number of cis Golgi glycosyltransferases which share a ϕ-(K/R)-X-L-X-(K/R) sequence bind directly to the δ- and ζ-subunits of COPI. Mutations of this N-tail motif impair binding to the COPI subunits, leading to mislocalization of the transferases to lysosomes. The physiological importance of these interactions is illustrated by mucolipidosis III patients with missense mutations in the N-tail of GlcNAc-1-phosphotransferase that cause the transferase to be rapidly degraded in lysosomes. These studies establish that direct binding of the N-tails of mammalian cis Golgi glycosyltransferases with COPI subunits is essential for recycling within the Golgi.

KEYWORDS:

COPI; Golgi; coatomer; glycosyltransferase

PMID:
30126980
PMCID:
PMC6130340
[Available on 2019-03-04]
DOI:
10.1073/pnas.1810291115
[Indexed for MEDLINE]

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