Maria E Kalland

Publications (2)13.48 Total impact

• Article: Modulation of proximal signaling in normal and transformed B cells by transmembrane adapter Cbp/PAG.

  Maria E Kalland, Silje A Solheim, Sigrid S Skånland, Kjetil Taskén, Torunn Berge
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  ABSTRACT: The transmembrane protein Cbp/PAG (Csk binding protein/phospho-protein associated with glycosphingolipid-enriched microdomains) has a negative regulatory role in T cell activation as an adapter for C-terminal Src kinase, Csk. In T cells, membrane docking of Csk is promoted by binding to FynT-phosphorylated Cbp/PAG (pTyr317) to allow targeting of substrates residing in lipid rafts. Here, we investigate a potential parallel position for Cbp/PAG and the Src kinase Lyn in early B cell receptor signaling. Using normal and transformed B cells, we have compared signal profiles of BCR-triggered responses created by phospho-specific flow cytometry. In human normal B cells, our data show that reduced Cbp/PAG levels leads to enhanced and prolonged activation of proximal signaling mediators, while over-expression of the adapter in normal, EBV-transformed cells results in reduced calcium flux. Taken together, our findings support a negative regulatory function for Cbp/PAG in proximal BCR signaling in these cells.
  Experimental Cell Research 05/2012; 318(14):1611-9. · 3.58 Impact Factor
• Article: High-resolution mapping of prostaglandin E2-dependent signaling networks identifies a constitutively active PKA signaling node in CD8+CD45RO+ T cells.

  Nikolaus G Oberprieler, Simone Lemeer, Maria E Kalland, Knut M Torgersen, Albert J R Heck, Kjetil Taskén
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  ABSTRACT: To analyze prostaglandin E(2) (PGE(2)) signaling in lymphoid cells, we introduce a multipronged strategy, combining temporal quantitative phosphoproteomics and phospho flow cytometry. We describe the PGE(2)-induced phosphoproteome by simultaneous monitoring of approximately 250 regulated phospho-epitopes, which, according to kinase prediction algorithms, originate from a limited number of kinase networks. Assessing these signaling pathways by phospho flow cytometry provided higher temporal resolution at various PGE(2) concentrations in multiple lymphoid cell subsets. This showed elevated levels of protein kinase A (PKA) signaling in unstimulated CD8(+)CD45RO(+) T cells, which correlated with suppressed proximal T-cell receptor signaling, indicating that PKA sets the threshold for activation. The combination of phosphoproteomics and high throughput phospho flow cytometry applied here provides a comprehensive generic framework for the analysis of signaling networks in mixed cell populations.
  Blood 09/2010; 116(13):2253-65. · 9.90 Impact Factor