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The concomitant tyrosine phosphorylation of the focal adhesion protein, paxillin, and the tyrosine kinase, focal adhesion kinase (FAK), in response to multiple stimuli including integrin-mediated cell adhesion suggests that paxillin phosphorylation is closely coupled to FAK activity. In the present study, we have identified a specific tyrosine residue(More)
Tyrosine phosphorylation of paxillin by the focal adhesion kinase (FAK) has been implicated as a signal transduction mechanism associated with cell adhesion and cytoskeletal reorganization. The potential role of serine phosphorylation of paxillin in these events has not been well characterized. In this study we have examined the phosphorylation profile of(More)
Although it has been known for many years that beta1 integrins undergo differential glycosylation in accordance with changes in cell phenotype, the potential role of N-glycosylation as a modulator of integrin function has received little attention. One reason for the relatively limited interest in this topic likely relates to the fact that much of the prior(More)
Colon adenocarcinomas are known to express elevated levels of alpha2-6 sialylation and increased activity of ST6Gal-I, the Golgi glycosyltransferase that creates alpha2-6 linkages. Elevated ST6Gal-I positively correlates with metastasis and poor survival, and therefore ST6Gal-I-mediated hypersialylation likely plays a role in colorectal tumor invasion.(More)
Despite many years of in vitro research confirming the effectiveness of RGD in promoting cell attachment to a wide variety of biomaterials, animal studies evaluating tissue responses to implanted RGD-functionalized substrates have yielded more variable results. The goals of this report are to present some of the reasons why cell culture studies may not(More)
Prior studies from our laboratory have shown that RGD peptides increase the attachment of mesenchymal stem cells (MSCs) to hydroxyapatite (HA), however, RGD does not induce cell spreading when coupled to this type of biomaterial. In an effort to improve MSC spreading, and possibly cell attachment, proteoglycan-binding peptides (KRSR or FHRRIKA) were(More)
PURPOSE Gliomas are the most frequently occurring primary malignancies in the brain, and glioblastoma is the most aggressive of these tumors. Protein kinase CK2 is composed of two catalytic subunits (α and/or α') and two β regulatory subunits. CK2 suppresses apoptosis, promotes neoangiogenesis, and enhances activation of the JAK/STAT, NF-κB, PI3K/AKT,(More)
The glycosyltransferase, ST6Gal-I, adds sialic acid in an α2-6 linkage to the N-glycans of membrane and secreted glycoproteins. Up-regulation of ST6Gal-I occurs in many cancers, including colon carcinoma, and correlates with metastasis and poor prognosis. However, mechanisms by which ST6Gal-I facilitates tumor progression remain poorly understood due to(More)
Macrophages play a central role in innate immunity, however mechanisms regulating macrophage survival are not fully understood. Herein we describe a novel apoptotic pathway involving α2-6 sialylation of the TNFR1 death receptor by the ST6Gal-I sialyltransferase. Variant glycosylation of TNFR1 has not previously been implicated in TNFR1 function, and little(More)
Integrin-binding peptides increase cell adhesion to naive hydroxyapatite (HA), however, in the body, HA becomes rapidly modified by protein adsorption. Previously we reported that, when combined with an adsorbed protein layer, RGD peptides interfered with cell adhesion to HA. In the current study we evaluated mesenchymal stem cell (MSC) interactions with HA(More)