Importance of Protein-tyrosine Phosphatase-α Catalytic Domains for Interactions with SHP-2 and Interleukin-1-induced Matrix Metalloproteinase-3 Expression

Abstract

Interleukin-1 (IL-1) induces extracellular matrix degradation as a result of increased expression of matrix metalloproteinases (MMPs).Reversible phosphorylation of proteins on tyrosine residues is a pivotal, post-translational modification in many signal transduction pathways. The extent of these modifications is determined by the balance between the activities of proteintyrosine kinases and phosphatases (1, 2). Whereas proteintyrosine kinases are thought to regulate the amplitude of responses to extracellular signals, protein-tyrosine phosphatases (PTPs) 2 may determine the rate and duration of these responses (3). For IL-1 signaling in adherent cells, tyrosine phosphorylation of focal adhesion proteins such as the focal adhesion kinase is a critical, rate-limiting process (4). Tyrosine phosphorylated proteins, such as focal adhesion kinase, paxillin, and Src family kinases, which are enriched in focal adhesions (5), influence the assembly, maturation, and disassembly of these adhesive structures (6 -9) and also impact signaling through focal adhesions (10). The dynamic and reversible nature of tyrosine phosphorylation of focal adhesion proteins suggests an important role for protein-tyrosine kinases and PTPs in focal adhesion-dependent signaling (11). There are numerous PTPs in focal adhesions, and, in particular, SHP-2 is recruited to focal adhesions upon integrin engagement (12-14). In the absence of SHP-2, the number of focal adhesions and actin stress fibers increases, which is associated with diminished spreading and motility (15, 16). Expression of a dominant-negative SHP-2 enhances the formation of focal adhesions and stress fibers (17). The dynamics of focal adhesion assembly and IL-1-induced signaling pathways, including Ca 2ϩ release and ERK phosphorylation, are dependent on phosphorylation of Tyr 542 of 18,19), which can in turn affect the phosphatase activity of SHP-2 (20).We recently reported that another PTP, namely PTP␣, plays a prominent role in the regulation of focal adhesions during cell adhesion, spreading, and motility (21). PTP␣ is a receptor-like PTP that can activate Src family kinases (e.g. Src and Fyn) via dephosphorylation of an inhibitory C-terminal tyrosine residue (22)(23)(24)(25)(26)(27). We have also shown that through its interactions with Src, PTP␣ controls IL-1 induced phosphorylation of the inositol 1,4,5-phosphate receptor and consequently, Ca 2ϩ release (28). Further, PTP␣ regulates formation of focal adhesions in response to mechanical force, strengthens connections between integrins and the cytoskeleton, and modulates cytoskeletal reorganization in response to integrin ligation (26,27). In the absence of PTP␣, fibroblasts demonstrated reduced spreading, increased numbers of abnormal focal adhesions, decreased tyrosine phosphorylation of focal * This work was supported by grants from the Canadian Institutes of Health Research (MOP 84254; to C. A. M. and G. P. D.). This work was also supported in part by National Institutes of Health Grant HL090669 (to G. P. D.) and funds ...

N-acetylglucosaminyltransferase V inhibits the invasion of trophoblast cells by attenuating MMP2/9 activity in early human pregnancy

“…The gelatinolytic activity was identified by gelatin zymographic analysis, as previously described [30,31]. A total of 10ml protein from the conditioned medium of HTR8/SVneo cells or placental villous explants underwent electrophoresis.…”

Interactions of the Protein-tyrosine Phosphatase-α with the Focal Adhesion Targeting Domain of Focal Adhesion Kinase Are Involved in Interleukin-1 Signaling in Fibroblasts

“…Our previous studies have partially characterized the roles of PTP␣ in focal adhesion-dependent IL-1 signaling (6,23,30); however, it is not known whether PTP␣ and FAK collaborate to regulate IL-1 signaling through FAs. Furthermore, we do not understand how PTP␣ is spatially sequestered to FAs and whether it interacts with FAK to enable adhesion-restricted IL-1 signaling.…”

“…PTP␣ is a critical adaptor in mediating functional links between FAs and the ER, a process that enables IL-1-induced Ca 2ϩ signaling and MMP-3 expression (6,30). To assess the fibroblasts used in the current experiments and to confirm key phenotypic features, we determined whether IL-1 affects the association of PTP␣ with FA-and ERassociated proteins in FAK ϩ/ϩ MEFs.…”

“…Spatial co-localization of interacting signaling molecules provides a pivotal regulatory locus for signal transduction. In adherent cells such as fibroblasts, the formation of FAs is required for IL-1-induced signaling cascades leading to tyrosine phosphorylation and activation of the focal adhesion kinase (11), Ca 2ϩ release from the endoplasmic reticulum (ER) (12,13), and activation of ERK (14,15), which ultimately result in regulating the expression of MMPs (6,16).…”

“…IL-1 stimulates the expression of the early response genes c-fos and c-jun as well as multiple cytokines such as interleukin-6 (IL-6) (3) and inflammatory factors that drive extracellular matrix degradation (4) via the up-regulation of various proteases, including members of the matrix metalloproteinase (MMP) 2 family such as MMP-9 in connective tissue cells (5). Enhanced expression of IL-6 (3), MMP-3 (6), and MMP-9 by IL-1 involves the activation of several interdependent signaling cascades that include the mitogen-activated protein kinase (MAPK) subfamily members, extracellular-signal regulated kinase (ERK), p38 MAPK, and stress-activated c-Jun N-terminal kinase (7). Although earlier studies have suggested a potential regulatory role of integrin receptors and the focal adhesion kinase (FAK) in MMP-9 expression (8), the mechanisms that coordinate the activation of these MAPK members in IL-6, MMP-3, and MMP-9 expression downstream of the IL-1 receptor are not well defined.…”