Delayed skin wound repair in proline-rich protein tyrosine kinase 2 knockout mice.

Proline-rich protein tyrosine kinase 2 (Pyk2) is a member of the focal adhesion kinase family. We used Pyk2 knockout (Pyk2-KO) mice to study the role of Pyk2 in cutaneous wound repair. We report that the rate of wound closure was delayed in Pyk2-KO compared with control mice.

Interstitial collagenase is a Brownian ratchet driven by proteolysis of collagen.

We show that activated collagenase (MMP-1) moves processively on the collagen fibril. The mechanism of movement is a biased diffusion with the bias component dependent on the proteolysis of its substrate, not adenosine triphosphate (ATP) hydrolysis. Inactivation of the enzyme by a single amino acid residue substitution in the active center eliminates the bias without noticeable effect on rate of diffusion.

Substrate binding of gelatinase B induces its enzymatic activity in the presence of intact propeptide.

Expression of gelatinase B (matrix metalloprotease 9) in human placenta is developmentally regulated, presumably to fulfill a proteolytic function. Here we demonstrate that gelatinolytic activity in situ, in tissue sections of term placenta, is co-localized with gelatinase B. Judging by molecular mass, however, all the enzyme extracted from this tissue was found in a proform.