Cell Signaling Technology

Product Pathways - Akt Signaling

Phospho-YB1 (Ser102) (C34A2) Rabbit mAb #2900

Applications Reactivity MW (kDa) Source Isotype
W H M Mk (R) (B) 49 Rabbit IgG

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  B=Bovine
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-YB1 (Ser102) (C34A2) Rabbit mAb detects endogenous levels of YB1 protein only when phosphorylated on Ser102.

Source / Purification

Monoclonal antibody is produced by immunizing rabbits with a synthetic phosphopeptide (KLH-coupled) corresponding to residues surrounding Ser102 of the human YB1 protein.

Western Blotting

Western Blotting

Western blot analysis of extracts from MCF-7 cells, serum-starved overnight and then either left untreated or treated with IGF-1 (50 ng/ml) for one hour, using Phospho-YB1 (Ser102) (C34A2) Rabbit mAb (upper) or YB1 Antibody #2749 (lower). Further treatment of the IGF-1-treated cell extracts with λ phosphatase depleted the phospho-specific YB1 signal (upper), but not total YB1 (lower).

Background

The Y-box binding protein 1 (YB1) belongs to a family of evolutionarily conserved, multifunctional Y-box proteins that bind single-stranded DNA and RNA and function as regulators of transcription, RNA metabolism, and protein synthesis (1). YB1 binds to Y-box sequences (TAACC) found in multiple gene promoters and can positively or negatively regulate transcription. YB1 activates genes associated with proliferation and cancer, such as cyclin A, cyclin B1, matrix metalloproteinase-2 (MMP-2), and the multi-drug resistance 1 (MDR1) gene (2-4). YB1 represses genes associated with cell death, including the Fas cell death-associated receptor and the p53 tumor suppressor gene (5-7). It also interacts with the RNA-splicing factor SRp30c and stabilizes interleukin 2 mRNA upon induction of T lymphocytes by interleukin 2 (8,9). The majority of YB1 protein localizes to the cytoplasm, with a minor pool found in the nucleus; however, nuclear localization appears to be critical for its role in promoting proliferation. Nuclear translocation is cell cycle-regulated, with YB1 protein accumulating in the nucleus during G1/S phase (2). In addition, nuclear translocation is induced in response to extracellular stimuli such as hyperthermia and UV irradiation, or treatment of cells with thrombin, interferons or insulin-like growth factor (IGF-1) (2,10). Treatment of the MCF-7 breast cancer cell line with IGF-1 results in Akt-mediated phosphorylation of YB1 on Ser102, which is required for nuclear translocation of YB1 and its ability to promote anchorage-independent growth (10). YB1 is over-expressed in many malignant tissues, including breast cancer, non-small cell lung carcinoma, ovarian adenocarcinomas, human osteosarcomas, colorectal carcinomas, and malignant melanomas, and nuclear expression correlates with high levels of proliferation, drug resistance, and poor tumor prognosis (2,7,10).

  1. Matsumoto, K. and Wolffe, A.P. (1998) Trends Cell Biol. 8, 318-23.
  2. Jurchott, K. et al. (2003) J. Biol. Chem. 278, 27988-96.
  3. Mertens, P.R. et al. (1997) J. Biol. Chem. 272, 22905-12.
  4. Uchiumi, T. et al. (1993) Cell Growth Differ. 4, 147-57.
  5. Lasham, A. et al. (2000) Gene 252, 1-13.
  6. Lasham, A. et al. (2003) J. Biol. Chem. 278, 35516-23.
  7. Homer, C. et al. (2005) Oncogene 24, 8314-25.
  8. Raffetseder, U. et al. (2003) J. Biol. Chem. 278, 18241-8.
  9. Chen, C.Y. et al. (2000) Genes Dev. 14, 1236-48.
  10. Sutherland, B.W. et al. (2005) Oncogene 24, 4281-92.

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