Cyclin-dependent kinase inhibitor 1B

Accession #/Synonyms:  AAF69497; CDKN4, KIP1, MEN1B, MEN4, P27Kip1,

Cyclin-dependent protein kinase inhibitors (CDKI) genes are considered the cell markers for cell senescence and DNA damage. Several of these inhibitors have characterized.  The one of the cyclin dependent protein kinase inhibitor, also known as Kip, play an important role in cell cycle and apoptosis in a variety of cell types.  There are two forms Kip cloned and are known to interact with cell division and cell cycle in various tissues including white blood cells, posterior regions of the lens and in the crypt cells of the gut.  Two forms of Kip are cloned, P27Kip-1 and P57Kip-2.  Over expression of P27(Kip1) arrests CHO-K1 derived cells in conditional G1-specific phase which are useful for screening cytotoxic drugs for ability to discriminate proliferating cells from mitotically inactive ones (1).   Induction of P27 (Kip1) in b cell lymphomas promotes growth arrest and apoptosis by inhibiting the induction of FOXO3 by PI3K and by down regulation of suppressor cMyc (2).  The cyclin-dependent kinase inhibitor p27 (Kip1) is an important cell cycle regulatory gene in breast cancer, and decreased p27 expression is associated with poor prognosis and is considered to be a mammary tumor suppressor gene (3).

In many human cancers, the cyclin-dependent kinase inhibitor p27(Kip1) is expressed at low or undetectable levels. The decreased p27(Kip1) expression allows cyclin-dependent kinase activity to cause cells to enter into S phase and correlates with poor patient survival. Inhibition of serine/threonine kinase Akt signaling by some pharmacological agents or by PTEN induces G(1) arrest, in part by up-regulating p27Kip1 (4). The Akt phosphorylates kip-1 at Ser 10 and Thr 187& 198.  P27Kip 1 is also phosphorylated by other kinase including protein kinase CK2 which is composed of 2 catalytic subunits (alfa) and 2 regulatory subunits (beta) subunits.  CK2 can phsophorylate many proteins that play important role in cell cycle.  In the presence of regulatory subunit (beta subunit) the CK2 kinase can phosphorylate P27(kip1) at position serine 83 (5).  Kip 1 is down regulated by MAP kinase reactivation in choroidal melanoma tumor-derived cell line (OCM-1) and this down-regulation is inhibited by MAP kinase inhibitor calpastatin (6). 

The kip1-selective rabbit antibodies were generated against peptides conjugated to KLH. Kip1 antibodies are affinity purified over immobilize non-phospho-antigen based chromatography.  The purified antibodies are stabilized in antibody stabilization buffer containing preservatives.  FabGennix Int. Inc. also provides a wide range of antibodies to protein kinases (receptor and non-receptor kianses) and kinase inhibitors.   FabGennix Inc. will also conjugate antibodies with fluorescent probes upon request at a reasonable cost.

For research use only, not for diagnostic or therapeutic use.