CycLex® Cdi1/KAP Protein Phosphatase Fluorometric Assay Kit

  • Target Cdi1
  • Code # CY-1356
  • Size 100 Assays
  • Price


A Cdk-interacting protein called Cdi1 (cyclin-dependent kinase interactor 1)/KAP (kinase associated phosphatase) was first identified as a novel G1- and S-phase dual-specificity phosphatase that associates with Cdk2 and/or Cdc2 by the interaction trap, a yeast genetic selection for interacting proteins (1, 2). In yeast, Cdi1/KAP interacts with cyclin-dependent kinases, including human Cdc2, Cdk2 and Cdk3, but not with Cdk4. In HeLa cells, Cdi1/KAP is expressed at the G1 to S transition, and the protein forms stable complexes with Cdk2. Further studies demonstrated that Cdi1/KAP binds to Cdk2 and dephosphorylates Thr160 when the associated cyclin subunit is degraded or dissociated (3). This suggested that Cdi1/KAP may inactivate Cdk2 or Cdc2 by removing phosphates from the cyclin complexes, contributing to cell cycle control (2). However, the physiological substrate(s) for tyrosine dephosphorylation of Cdi1/KAP has not yet been identified. Phosphatases have also been shown to play an important role in regulating a variety of signal transduction pathways that have a bearing on cancer (4-6). It was reported that the Cdi1/KAP gene is overexpressed in human breast and prostate cancer using differential screening and that breast and prostate malignancies are associated with high levels of KAP expression (7).
  • Components:
    • 10x Assay Buffer
    • 10x 3-o-methyl fluorescein phosphate (OMFP)
    • Recombinant Human Cdi1/KAP
    • 100x Cdi1 Inhibitor
    • Stop Solution
  • Description:

    The CycLex Cdi1/KAP Fluorometric Assay Kit is a fluorometric and non-radioactive assay designed to measure the activity of Cdi1/KAP protein phosphatase It can be used for 100 assays.

  • Product Type:
  • Short Description:

    CycLex Cdi1/KAP Protein Phosphatase Fluorometric Assay Kit.

  • Size:
    100 Assays
  • Storage Temperature:
    -20°C. Please refer to datasheet for additional information
  • Target:
  1. Hyeog Kang, Jeong-Yong Suh, Young-Sang Jung, Jae-Won Jung, Myung K. Kim, Jay H. Chung; Peptide Switch Is Essential for Sirt1 Deacetylase Activity. Mol. Cell. 44, 203, 2011,
  2. Shan-Shan Yu, Yi Cai1, Jian-Tao Ye, Rong-Biao Pi, Shao-Rui Chen, Pei-Qing Liu, Xiao-Yan Shen, Yong Ji; Sirtuin 6 protects cardiomyocytes from hypertrophy in vitro via inhibition of NF-κB-dependent transcriptional activity. Br J Pharmacol. 168: 117-28. 2012
  1. Gyuris, J.; Golemis, E.; Chertkov, H.; Brent, R. Cdi1, a human G1 and S phase protein phosphatase that associates with Cdk2. Cell, 75: 791-803, 1993.
  2. Hannon, G. J.; Casso, D.; Beach, D. KAP: a dual specificity phosphatase that interacts with cyclin-dependent kinases. Proc. Nat. Acad. Sci. 91: 1731-1735, 1994.
  3. Poon RY and Hunter T. Dephosphorylation of Cdk2 Thr160 by the cyclin-dependent kinase-interacting phosphatase KAP in the absence of cyclin. Science, 270: 90-3, 1995.
  4. Denu, J. M., M. A. Stuckey, M. Saper, and J. E. Dixon. Form and function in protein dephosphorylation. Cell, 87: 361-364, 1996.
  5. Kinzler, K. W., and B. Vogelstein. Landscaping the cancer terrain. Science, 280: 1036-1037, 1998.
  6. Parsons, R. Phosphatases and tumorigenesis. Curr. Opin. Oncol. 10: 88-91, 1998.
  7. Lee SW, Reimer CL, Fang L, Iruela-Arispe ML, Aaronson SA. Overexpression of kinase-associated phosphatase (KAP) in breast and prostate cancer and inhibition of the transformed phenotype by antisense KAP expression. Mol Cell Biol. 20: 1723-32, 2000