title: Expression of the p16 and p15 cyclin-dependent kinase inhibitors in lymphocyte activation and neuronal differentiation.
abstract: The cyclin-dependent kinase inhibitors p16INK4/MTS1 and p15INK4B/MTS2 have been mapped to a region in chromosome 9 (921) that is deleted frequently in acute lymphoblastic leukemias and malignant gliomas. To gain insight into the functions of these inhibitors in lymphocytes and neuronal cells, we studied the expression of p15 and p16 during lymphocyte mitogenesis and neuronal differentiation. Expression of p15 was extinguished during lymphocyte activation, concomitant with an increase in retinoblastoma kinase activity. The differentiation of the embryonic teratocarcinoma cell line NT2 into postmitotic neurons (hNT) was associated with enhanced expression of p15 and p16 proteins. These findings suggest that p15 and p16 play a role in maintaining cell quiescence in lymphocytes and neuronal cells, respectively. Deletions of these genes may thus promote unrestrained growth.
authors.affiliation: Sam and Rose Stein Institute for Research on Aging, University of California, San Diego, La Jolla 92093-0663, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: Lois
authors.forename: L T
authors.initials: LT
authors.lastname: Cooper
authors.forename: Y
authors.initials: Y
authors.lastname: Geng
authors.forename: T
authors.initials: T
authors.lastname: Nobori
authors.forename: D
authors.initials: D
authors.lastname: Carson
mesh_terms: D001483:Base Sequence; D002352:Carrier Proteins / Q000032:analysis*; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D006801:Humans; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D009474:Neurons / Q000502:physiology*; D010766:Phosphorylation; D011090:Polyenes / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D020123:Sirolimus; D025521:Tumor Suppressor Proteins
chemical_list: C493966:CDKN2B protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D011090:Polyenes; D047428:Protein Kinase Inhibitors; D025521:Tumor Suppressor Proteins; D020123:Sirolimus