scholarly journals Receptor Tyrosine Phosphatase β (RPTPβ) Activity and Signaling Are Attenuated by Glycosylation and Subsequent Cell Surface Galectin-1 Binding

2008 ◽  
Vol 283 (48) ◽  
pp. 33026-33035 ◽  
Author(s):  
Karen L. Abbott ◽  
Russell T. Matthews ◽  
Michael Pierce
Keyword(s):  
Cell Surface ◽  
Tyrosine Phosphatase ◽  
Receptor Tyrosine Phosphatase

scholarly journals Identification of the atypical cadherin FAT1 as a novel glypican-3 interacting protein in liver cancer cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Panpan Meng ◽  
Yi-Fan Zhang ◽  
Wangli Zhang ◽  
Xin Chen ◽  
Tong Xu ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Surface ◽  
Transmembrane Protein ◽  
Tyrosine Phosphatase ◽  
Interacting Protein ◽  
Extracellular Signaling ◽  
Putative Receptor ◽  
Elevated Expression ◽  
A Cell ◽  
Receptor Tyrosine Phosphatase

AbstractGlypican-3 (GPC3) is a cell surface heparan sulfate proteoglycan that is being evaluated as an emerging therapeutic target in hepatocellular carcinoma (HCC). GPC3 has been shown to interact with several extracellular signaling molecules, including Wnt, HGF, and Hedgehog. Here, we reported a cell surface transmembrane protein (FAT1) as a new GPC3 interacting protein. The GPC3 binding region on FAT1 was initially mapped to the C-terminal region (Q14517, residues 3662-4181), which covered a putative receptor tyrosine phosphatase (RTP)-like domain, a Laminin G-like domain, and five EGF-like domains. Fine mapping by ELISA and flow cytometry showed that the last four EGF-like domains (residues 4013-4181) contained a specific GPC3 binding site, whereas the RTP domain (residues 3662-3788) and the downstream Laminin G-2nd EGF-like region (residues 3829-4050) had non-specific GPC3 binding. In support of their interaction, GPC3 and FAT1 behaved concomitantly or at a similar pattern, e.g. having elevated expression in HCC cells, being up-regulated under hypoxia conditions, and being able to regulate the expression of EMT-related genes Snail, Vimentin, and E-Cadherin and promoting HCC cell migration. Taken together, our study provides the initial evidence for the novel mechanism of GPC3 and FAT1 in promoting HCC cell migration.

scholarly journals Loss of T-Cell Protein Tyrosine Phosphatase Induces Recycling of the Platelet-derived Growth Factor (PDGF) β-Receptor but Not the PDGF α-Receptor

2006 ◽  
Vol 17 (11) ◽  
pp. 4846-4855 ◽  
Author(s):  
Susann Karlsson ◽  
Katarzyna Kowanetz ◽  
Åsa Sandin ◽  
Camilla Persson ◽  
Arne Östman ◽  
...  
Keyword(s):  
T Cell ◽  
Growth Factor ◽  
Cell Surface ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Cell Protein ◽  
Protein Tyrosine ◽  
Β Receptor

We have previously shown that the T-cell protein tyrosine phosphatase (TC-PTP) dephosphorylates the platelet-derived growth factor (PDGF) β-receptor. Here, we show that the increased PDGF β-receptor phosphorylation in TC-PTP knockout (ko) mouse embryonic fibroblasts (MEFs) occurs primarily on the cell surface. The increased phosphorylation is accompanied by a TC-PTP–dependent, monensin-sensitive delay in clearance of cell surface PDGF β-receptors and delayed receptor degradation, suggesting PDGF β-receptor recycling. Recycled receptors could also be directly detected on the cell surface of TC-PTP ko MEFs. The effect of TC-PTP depletion was specific for the PDGF β-receptor, because PDGF α-receptor homodimers were cleared from the cell surface at the same rate in TC-PTP ko MEFs as in wild-type MEFs. Interestingly, PDGF αβ-receptor heterodimers were recycling. Analysis by confocal microscopy revealed that, in TC-PTP ko MEFs, activated PDGF β-receptors colocalized with Rab4a, a marker for rapid recycling. In accordance with this, transient expression of a dominant-negative Rab4a construct increased the rate of clearance of cell surface receptors on TC-PTP ko MEFs. Thus, loss of TC-PTP specifically redirects the PDGF β-receptor toward rapid recycling, which is the first evidence of differential trafficking of PDGF receptor family members.

Insights into the ontogeny and activation of T cells

1994 ◽  
Vol 40 (11) ◽  
pp. 2128-2131 ◽  
Author(s):  
T W Mak
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Cell Surface ◽  
Immune Responses ◽  
Tyrosine Phosphatase ◽  
T Cell Development ◽  
Cell Development ◽  
Mutant Mice ◽  
Target Cells

Abstract T lymphocytes recognize antigen peptides and major histocompatibility complex products through their T-cell antigen receptors (TcR), consisting of alpha and beta chains. The interaction between T cells and their target cells or antigen-presenting cells is also assisted by a series of other cell-surface polypeptides, most notably CD4 and CD8, which are selectively expressed on mature helper/inducer and killer/suppressor T cells, respectively. Upon engagement of their ligands, a series of signals is transduced intracytoplasmically via some of these molecules and their associated proteins. Perhaps the most important enzyme in this signal transduction process is the lymphocyte-specific tyrosine kinase lck. Another important component is the cell-surface tyrosine phosphatase CD45. This molecule is alternatively spliced and the different isoforms are expressed on the various hematopoietic and lymphopoietic cells. Signaling through the TcR-CD4 D8-lck-CD45 complex is thought to be insufficient to activate T lymphocytes. A costimulatory signal is believed to be essential, and many investigators have suggested that CD28, a ligand for B7/BB1, is such a signal. Immune responses are also controlled by a number of cytokines and soluble factors. Signaling through the tumor necrosis factor receptor p55 is required for clearance of intracellular pathogens. Transcriptional factors involved in controlling interferon production are also important in T-cell development and immune responses. In an attempt to gain a better understanding of the roles of these molecules in T-lymphocyte functions and ontogeny, we generated a series of mutant mice with disruptions in the genes coding for these molecules. We are analyzing the mutant mice to evaluate the importance of these genes in T-cell development.

Receptor tyrosine phosphatase sigma (RPTPσ) regulates, p250GAP, a novel substrate that attenuates Rac signaling

2010 ◽  
Vol 22 (11) ◽  
pp. 1626-1633 ◽  
Author(s):  
Mélanie J. Chagnon ◽  
Chia-Lun Wu ◽  
Takanobu Nakazawa ◽  
Tadashi Yamamoto ◽  
Masaharu Noda ◽  
...  
Keyword(s):  
Tyrosine Phosphatase ◽  
Receptor Tyrosine Phosphatase
Sign in / Sign up

Export Citation Format

Share Document