TITLE:
Arg-Ser-775, 792 and 823 in Spacer Region of ADAMTS-18 Is Critical for Thrombin Cleavage
AUTHORS:
Jian Tang, Wei Huang, Ning Shen, Tao Hong, Suying Dang, Wei Zhang
KEYWORDS:
ADAMTS-18, Thrombin, Cleavage, Mass Spectrum
JOURNAL NAME:
Health,
Vol.6 No.18,
October
16,
2014
ABSTRACT: Cleavage of ADAMTS-18
by thrombin represents a new mechanism of platelet thrombus clearance via the
release of active ~45-kDa C-terminal fragments that induces oxidative platelet
fragmentation. The exact cleavage sites remain unclear, but Arg (R)775/Ser
(S)776 in
spacer region of ADAMTS-18 has been shown to be one of the cleavage sites of
thrombin. Here, we demonstrate that R792/S793 and R823/S824 are also thrombin cleavage sites by sequence analysis, amino acid mutation and
mass spectrometry assay. All these cleavage sites are thrombin-specific and
insensitive to other enzymes tested (e.g. cathepsin D or trypsin). Simultaneous
mutation of R775, 792, 823 to S775, 792, 823 in
ADAMTS-18 completely abrogated the cleavage by thrombin and the generation of
active C-terminal 45-kDa fragments. Together with previous study, a total of
three thrombin-specific cleavage sites have been identified in spacer region of
ADAMTS-18.