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Differential regulation of TCR-mediated gene transcription by Vav family members.

Zakaria S, Gomez TS, Savoy DN, McAdam S, Turner M, Abraham RT, Billadeau DD - J. Exp. Med. (2004)

Bottom Line: However, depletion of Vav1 but not Vav3 protein by RNA interference affects TCR-mediated IL-2 promoter activity.In contrast, Vav3 function is specifically required for coupling TCR stimulation to serum response element-mediated gene transcription.These data indicate that, although both Vav proteins are biochemically coupled to the TCR, they regulate distinct molecular pathways leading to defined gene transcriptional events.

View Article: PubMed Central - PubMed

Affiliation: Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.

ABSTRACT
Although all three Vav family members are expressed in T lymphocytes, the role that Vav3 plays in T cell activation is poorly defined. Here we show that, like Vav1, Vav3 undergoes rapid tyrosine phosphorylation after T cell receptor (TCR) cross-linkage and interacts with the adaptor molecules SLP76 and 3BP2 in a SH2-dependent manner. However, depletion of Vav1 but not Vav3 protein by RNA interference affects TCR-mediated IL-2 promoter activity. In contrast, Vav3 function is specifically required for coupling TCR stimulation to serum response element-mediated gene transcription. These data indicate that, although both Vav proteins are biochemically coupled to the TCR, they regulate distinct molecular pathways leading to defined gene transcriptional events.

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Vav proteins couple to the T cell receptor. (A) Jurkat T cells or (B) a CD4+ T cell clone were treated as indicated. The different Vav isoforms were specifically immunoprecipitated (Vav1, top; Vav2, middle; and Vav3, bottom) using Vav-specific polyclonal rabbit antisera. The immunoprecipitates were resolved by SDS-PAGE, transferred to a nylon membrane, and probed with anti-pTyr (top panel in each set) or anti-Vav (bottom panel in each set).
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fig1: Vav proteins couple to the T cell receptor. (A) Jurkat T cells or (B) a CD4+ T cell clone were treated as indicated. The different Vav isoforms were specifically immunoprecipitated (Vav1, top; Vav2, middle; and Vav3, bottom) using Vav-specific polyclonal rabbit antisera. The immunoprecipitates were resolved by SDS-PAGE, transferred to a nylon membrane, and probed with anti-pTyr (top panel in each set) or anti-Vav (bottom panel in each set).

Mentions: To determine the role of Vav3 in TCR signaling, we initially compared the kinetics of tyrosine phosphorylation of the three distinct Vav isoforms after TCR cross-linkage in the Jurkat T cell line. Although basal levels of Vav1 tyrosine phosphorylation are apparent, there is little or no detectable basal tyrosine phosphorylation of Vav2 or Vav3 (Fig. 1 A). However, upon TCR cross-linking all three Vav family members undergo rapid tyrosine phosphorylation with peak phosphorylation attained at 1 min poststimulation and a gradual decline in phosphotyrosine content observed at later time points. Similar results were observed when Vav1 and Vav3 tyrosine phosphorylation was measured after TCR cross-linkage in a CD4+ human T cell clone (Fig. 1 B). Thus, all three Vav proteins couple to the TCR and show similar kinetics of tyrosine phosphorylation.


Differential regulation of TCR-mediated gene transcription by Vav family members.

Zakaria S, Gomez TS, Savoy DN, McAdam S, Turner M, Abraham RT, Billadeau DD - J. Exp. Med. (2004)

Vav proteins couple to the T cell receptor. (A) Jurkat T cells or (B) a CD4+ T cell clone were treated as indicated. The different Vav isoforms were specifically immunoprecipitated (Vav1, top; Vav2, middle; and Vav3, bottom) using Vav-specific polyclonal rabbit antisera. The immunoprecipitates were resolved by SDS-PAGE, transferred to a nylon membrane, and probed with anti-pTyr (top panel in each set) or anti-Vav (bottom panel in each set).
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Related In: Results  -  Collection

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fig1: Vav proteins couple to the T cell receptor. (A) Jurkat T cells or (B) a CD4+ T cell clone were treated as indicated. The different Vav isoforms were specifically immunoprecipitated (Vav1, top; Vav2, middle; and Vav3, bottom) using Vav-specific polyclonal rabbit antisera. The immunoprecipitates were resolved by SDS-PAGE, transferred to a nylon membrane, and probed with anti-pTyr (top panel in each set) or anti-Vav (bottom panel in each set).
Mentions: To determine the role of Vav3 in TCR signaling, we initially compared the kinetics of tyrosine phosphorylation of the three distinct Vav isoforms after TCR cross-linkage in the Jurkat T cell line. Although basal levels of Vav1 tyrosine phosphorylation are apparent, there is little or no detectable basal tyrosine phosphorylation of Vav2 or Vav3 (Fig. 1 A). However, upon TCR cross-linking all three Vav family members undergo rapid tyrosine phosphorylation with peak phosphorylation attained at 1 min poststimulation and a gradual decline in phosphotyrosine content observed at later time points. Similar results were observed when Vav1 and Vav3 tyrosine phosphorylation was measured after TCR cross-linkage in a CD4+ human T cell clone (Fig. 1 B). Thus, all three Vav proteins couple to the TCR and show similar kinetics of tyrosine phosphorylation.

Bottom Line: However, depletion of Vav1 but not Vav3 protein by RNA interference affects TCR-mediated IL-2 promoter activity.In contrast, Vav3 function is specifically required for coupling TCR stimulation to serum response element-mediated gene transcription.These data indicate that, although both Vav proteins are biochemically coupled to the TCR, they regulate distinct molecular pathways leading to defined gene transcriptional events.

View Article: PubMed Central - PubMed

Affiliation: Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.

ABSTRACT
Although all three Vav family members are expressed in T lymphocytes, the role that Vav3 plays in T cell activation is poorly defined. Here we show that, like Vav1, Vav3 undergoes rapid tyrosine phosphorylation after T cell receptor (TCR) cross-linkage and interacts with the adaptor molecules SLP76 and 3BP2 in a SH2-dependent manner. However, depletion of Vav1 but not Vav3 protein by RNA interference affects TCR-mediated IL-2 promoter activity. In contrast, Vav3 function is specifically required for coupling TCR stimulation to serum response element-mediated gene transcription. These data indicate that, although both Vav proteins are biochemically coupled to the TCR, they regulate distinct molecular pathways leading to defined gene transcriptional events.

Show MeSH