The p21 Cdk-interacting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases

The expression of the human Ki-67 protein is strictly associated with cell proliferation. During interphase, the antigen can be exclusively detected within the nucleus, whereas in mitosis most of the protein is relocated to the surface of the chromosomes. The fact that the Ki-67 protein is present during all active phases of the cell cycle (G(1), S, G(2), and mitosis), but is absent from resting cells (G(0)), makes it an excellent marker for determining the so-called growth fraction of a given cell population. In the first part of this study, the term proliferation marker is discussed and examples of the applications of anti-Ki-67 protein antibodies in diagnostics of human tumors are given. The fraction of Ki-67-positive tumor cells (the Ki-67 labeling index) is often correlated with the clinical course of the disease. The best-studied examples in this context are carcinomas of the prostate and the breast. For these types of tumors, the prognostic value for survival and tumor recurrence has repeatedly been proven in uni- and multivariate analysis. The preparation of new monoclonal antibodies that react with the Ki-67 equivalent protein from rodents now extends the use of the Ki-67 protein as a proliferation marker to laboratory animals that are routinely used in basic research. The second part of this review focuses on the biology of the Ki-67 protein. Our current knowledge of the Ki-67 gene and protein structure, mRNA splicing, expression, and cellular localization during the cell-division cycle is summarized and discussed. Although the Ki-67 protein is well characterized on the molecular level and extensively used as a proliferation marker, the functional significance still remains unclear. There are indications, however, that Ki-67 protein expression is an absolute requirement for progression through the cell-division cycle.

The Ki‐67 protein: From the known and the unknown

Interferon-gamma (IFN-gamma) coordinates a diverse array of cellular programs through transcriptional regulation of immunologically relevant genes. This article reviews the current understanding of IFN-gamma ligand, receptor, signal transduction, and cellular effects with a focus on macrophage responses and to a lesser extent, responses from other cell types that influence macrophage function during infection. The current model for IFN-gamma signal transduction is discussed, as well as signal regulation and factors conferring signal specificity. Cellular effects of IFN-gamma are described, including up-regulation of pathogen recognition, antigen processing and presentation, the antiviral state, inhibition of cellular proliferation and effects on apoptosis, activation of microbicidal effector functions, immunomodulation, and leukocyte trafficking. In addition, integration of signaling and response with other cytokines and pathogen-associated molecular patterns, such as tumor necrosis factor-alpha, interleukin-4, type I IFNs, and lipopolysaccharide are discussed.

https://jlb.onlinelibrary.wiley.com/doi/epdf/10.1189/jlb.0603252

Interferon-γ: an overview of signals, mechanisms and functions

The homeostasis of animals is regulated not only by the growth and differentiation of cells, but also by cell death through a process known as apoptosis. Apoptosis is mediated by members of the caspase family of proteases, and eventually causes the degradation of chromosomal DNA. A caspase-activated deoxyribonuclease (CAD) and its inhibitor (ICAD) have now been identified in the cytoplasmic fraction of mouse lymphoma cells. CAD is a protein of 343 amino acids which carries a nuclear-localization signal; ICAD exists in a long and a short form. Recombinant ICAD specifically inhibits CAD-induced degradation of nuclear DNA and its DNase activity. When CAD is expressed with ICAD in COS cells or in a cell-free system, CAD is produced as a complex with ICAD: treatment with caspase 3 releases the DNase activity which causes DNA fragmentation in nuclei. ICAD therefore seems to function as a chaperone for CAD during its synthesis, remaining complexed with CAD to inhibit its DNase activity; caspases activated by apoptotic stimuli then cleave ICAD, allowing CAD to enter the nucleus and degrade chromosomal DNA.

A caspase-activated DNase that degrades DNA during apoptosis, and its inhibitor ICAD

https://www.cell.com/cell/pdf/0092-8674(94)90572-X.pdf

Cloning of p27Kip1, a cyclin-dependent kinase inhibitor and a potential mediator of extracellular antimitogenic signals

Nuclear targeting sequences--a consensus?

Immunoassay for urothelial cancers that detects DNA replication protein Mcm5 in urine.

Summary Bulk nuclear export of messenger ribonucleoproteins (mRNPs) through nuclear pore complexes (NPCs) is mediated by NXF1. It binds mRNPs through adaptor proteins such as ALY [1, 2] and SR splicing factors [3] and mediates translocation through the central NPC transport channel via transient interactions with FG nucleoporins [4–10]. Here, we show that mammalian cells require GANP (germinal center-associated nuclear protein) for efficient mRNP nuclear export and for efficient recruitment of NXF1 to NPCs. Separate regions of GANP show local homology to FG nucleoporins, the yeast mRNA export factor Sac3p, and the mammalian MCM3 acetyltransferase. GANP interacts with both NXF1 and NPCs and partitions between NPCs and the nuclear interior. GANP depletion inhibits mRNA export, with retention of mRNPs and NXF1 in punctate foci within the nucleus. The GANP N-terminal region that contains FG motifs interacts with the NXF1 FG-binding domain. Overexpression of this GANP fragment leads to nuclear accumulation of both poly(A) + RNA and NXF1. Treatment with transcription inhibitors redistributes GANP from NPCs into foci throughout the nucleus. These results establish GANP as an integral component of the mammalian mRNA export machinery and suggest a model whereby GANP facilitates the transfer of NXF1-containing mRNPs to NPCs.

https://www.cell.com/current-biology/pdf/S0960-9822(09)01995-2.pdf

Report mRNA Export from Mammalian Cell Nuclei Is Dependent on GANP

Determination of cellular growth abnormality, particularly cancerous abnormality, by detection of target polypeptides or encoding mRNA, where the target polypeptides are members of the preinitiation complex of DNA replication in tissue, cells or fluid. Target polypeptides include CDC6, MCM2, MCM3, MCM4, MCM5, MCM6 and MCM7. Test samples include tissue of the cervix (both biopsy and smear samples), breast, colon, lung, bladder, skin, larynx, oesophagus, bronchus, lymph nodes and urinary tract (both biopsy and cytology smear samples), in determination of cancerous and pre-cancerous cellular growth abnormality, and cells spun from urine, blood and serum, in determination of haematological malignancies and evidence of metastatic sarcoma and carcinoma.

Detection of dysplastic or neoplastic cells using anti-MCM5 antibodies

Determination of cellular growth abnormality, particularly cancerous abnormality, by detection of target polypeptides or encoding mRNA, where the target polypeptides are members of the preinitiation complex of DNA replication in tissue, cells or fluid. Target polypeptides include CDC6, MCM2, MCM3, MCM4, MCM5, MCM6 and MCM7. Test samples include tissue of the cervix (both biopsy and smear samples), breast, colon, lung, bladder, skin, larynx, oesophagus, bronchus, lymph nodes and urinary tract (both biopsy and cytology smear samples), in determination of cancerous and precancerous cellular growth abnormality, and cells spun from urine, blood and serum, in determination of haematological malignancies and evidence of metastatic sarcoma and carcinoma.

Ronald Alfred Laskey

Papers

Nuclear targeting sequences--a consensus?

Immunoassay for urothelial cancers that detects DNA replication protein Mcm5 in urine.

Report mRNA Export from Mammalian Cell Nuclei Is Dependent on GANP

Detection of dysplastic or neoplastic cells using anti-MCM5 antibodies

Detection of dysplastic or neoplastic cells using anti-mcm2 antibodies