Fig. 4: Schematic representation of the uPA activation and cleavage. | British Journal of Cancer

Fig. 4: Schematic representation of the uPA activation and cleavage.

From: Differentiating borderline HER2-expressing and HER2-positive cancers from other subtypes using serum urokinase plasminogen activator

Fig. 4: Schematic representation of the uPA activation and cleavage.The alternative text for this image may have been generated using AI.

a Schematic representation of the uPA activation and proteolytic cleavage. The single-chain precursor form, pro-uPA, contains 3 structural domains: the growth factor domain (GFD), kringle domain (KD), and catalytic domain (CD). Activation of pro-uPA occurs via cleavage at the Lys158–Ile159 peptide bond, producing the two-chain uPA held together by a disulphide bridge (HMW uPA, ca. 54 kDa). 2nd proteolytic cleavage between Lys135 and Lys136 yields two fragments: the amino-terminal fragment (ATF), including GFD-KD, and the catalytic LMW form (LMW uPA, ca. 33 kDa), comprising the serine protease domain. Adapted from [30]. b uPA binding to uPAR dimers on the cell surface facilitates 2nd proteolytic cleavage leading to LMW uPA release into the bloodstream.

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