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 ◽  
...  

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.

2000 ◽  
Vol 275 (21) ◽  
pp. 16219-16226 ◽  
Author(s):  
Marina Kovalenko ◽  
Karsten Denner ◽  
Jill Sandström ◽  
Camilla Persson ◽  
Steffen Groβ ◽  
...  

1998 ◽  
Vol 18 (3) ◽  
pp. 1622-1634 ◽  
Author(s):  
Tony Tiganis ◽  
Anton M. Bennett ◽  
Kodimangalam S. Ravichandran ◽  
Nicholas K. Tonks

ABSTRACT T-cell protein tyrosine phosphatase (TCPTP) exists as two forms generated by alternative splicing: a 48-kDa endoplasmic reticulum (ER)-associated form (TC48) and a 45-kDa nuclear form (TC45). To identify TCPTP substrates, we have generated substrate-trapping mutants, in which the invariant catalytic acid of TCPTP (D182) is mutated to alanine. The TCPTP D182A substrate-trapping mutants were transiently overexpressed in COS cells, and their ability to form complexes with tyrosine-phosphorylated (pTyr) proteins was assessed. No pTyr proteins formed complexes with wild-type TCPTP. In contrast, TC48-D182A formed a complex in the ER with pTyr epidermal growth factor receptor (EGFR). In response to EGF, TC45-D182A exited the nucleus and accumulated in the cytoplasm, where it bound pTyr proteins of ∼50, 57, 64, and 180 kDa. Complex formation was disrupted by vanadate, highlighting the importance of the PTP active site in the interaction and supporting the characterization of these proteins as substrates. Of these TC45 substrates, the ∼57- and 180-kDa proteins were identified as p52Shc and EGFR, respectively. We examined the effects of TC45 on EGFR signaling and observed that it did not modulate EGF-induced activation of p42Erk2. However, TC45 inhibited the EGF-induced association of p52Shc with Grb2, which was attributed to the ability of the PTP to recognize specifically p52Shc phosphorylated on Y239. These results indicate that TC45 recognizes not only selected substrates in a cellular context but also specific sites within substrates and thus may regulate discrete signaling events.


2001 ◽  
Vol 276 (28) ◽  
pp. 26036-26043 ◽  
Author(s):  
Ernest Asante-Appiah ◽  
Kristen Ball ◽  
Kevin Bateman ◽  
Kathryn Skorey ◽  
Rick Friesen ◽  
...  

2019 ◽  
Vol 58 (9) ◽  
pp. 1640-1647
Author(s):  
Liza D. Morales ◽  
Anna K. Archbold ◽  
Serena Olivarez ◽  
Thomas J. Slaga ◽  
John DiGiovanni ◽  
...  

2013 ◽  
Vol 1834 (10) ◽  
pp. 1988-1997 ◽  
Author(s):  
Mikko Ylilauri ◽  
Elina Mattila ◽  
Elisa M. Nurminen ◽  
Jarmo Käpylä ◽  
Sanna P. Niinivehmas ◽  
...  

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