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Fucosylation Promotes Secretion

The ADAMTS superfamily of proteins contains several metalloproteases as well as ADAMTS-like molecules that lack proteolytic activity. Their common feature is the presence of one or more thrombospondin type-1 repeats (TSRs). In these co-Papers of the Week, the authors show that fucosylation of TSR repeats is essential for secretion of two ADAMTS family members.

Punctin-1 contains four fucosylated TSRs that are needed for secretion.

ADAMTS13 is a plasma metalloproteinase that cleaves von Willebrand factor into smaller, less thrombogenic forms. The protease contains eight TSRs, seven of which contain a consensus sequence for the direct addition of fucose to the hydroxyl group of serine or threonine. Lindsay M. Ricketts and colleagues showed that at least six of the TSRs are modified with glucose-1,3-fucose. Mutation of the modified serines to alanine reduced ADAMTS13 secretion. Similarly, reducing the expression of the enzyme that transfers fucose to the serines decreased ADAMTS13 secretion. Ricketts et al. also observed that when ADAMTS13 was expressed in a cell line unable to synthesize GDP-fucose (the donor for fucose addition), secretion of the metalloproteinase was diminished.

ADAMTS-like 1, also known as punctin-1, is a secreted glycoprotein that has an affinity for extracellular matrix. It has four TSRs with four consensus sites for O-fucosylation and one site for N-linked oligosaccharide attachment. Lauren W. Wang and colleagues showed that all four repeats contain fucose and that mutation of the putative sugar-containing residues decreased the secretion of punctin-1. Similarly, expression of punctin-1 in cells that were unable to convert GDP-mannose to GDP-fucose substantially decreased the levels of secreted protein. These levels were restored when the cells were cultured with exogenous L-fucose.

Taken together, these findings indicate that fucosylation is needed for secretion of ADAMTS proteins.

FOOTNOTES

See referenced article, J. Biol. Chem. 2007, 282, 17014-17023, 17024-17031

Fucosylation Promotes Secretion

The ADAMTS superfamily of proteins contains several metalloproteases as well as ADAMTS-like molecules that lack proteolytic activity. Their common feature is the presence of one or more thrombospondin type-1 repeats (TSRs). In these co-Papers of the Week, the authors show that fucosylation of TSR repeats is essential for secretion of two ADAMTS family members.

Punctin-1 contains four fucosylated TSRs that are needed for secretion.

ADAMTS13 is a plasma metalloproteinase that cleaves von Willebrand factor into smaller, less thrombogenic forms. The protease contains eight TSRs, seven of which contain a consensus sequence for the direct addition of fucose to the hydroxyl group of serine or threonine. Lindsay M. Ricketts and colleagues showed that at least six of the TSRs are modified with glucose-1,3-fucose. Mutation of the modified serines to alanine reduced ADAMTS13 secretion. Similarly, reducing the expression of the enzyme that transfers fucose to the serines decreased ADAMTS13 secretion. Ricketts et al. also observed that when ADAMTS13 was expressed in a cell line unable to synthesize GDP-fucose (the donor for fucose addition), secretion of the metalloproteinase was diminished.

ADAMTS-like 1, also known as punctin-1, is a secreted glycoprotein that has an affinity for extracellular matrix. It has four TSRs with four consensus sites for O-fucosylation and one site for N-linked oligosaccharide attachment. Lauren W. Wang and colleagues showed that all four repeats contain fucose and that mutation of the putative sugar-containing residues decreased the secretion of punctin-1. Similarly, expression of punctin-1 in cells that were unable to convert GDP-mannose to GDP-fucose substantially decreased the levels of secreted protein. These levels were restored when the cells were cultured with exogenous L-fucose.

Taken together, these findings indicate that fucosylation is needed for secretion of ADAMTS proteins.

FOOTNOTES

See referenced article, J. Biol. Chem. 2007, 282, 17014-17023, 17024-17031

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