Cell Division Cycle

All organisms (single and multi-cellular) rely upon reiteration of growth and division of existing cells under favorable conditions. During each round of this process, the cell cycles through an ordered series of events in which its genetic information is duplicated and then divided among two daughter cells. These events are tightly regulated and certain checkpoints must be passed in order for the cell cycle to be completed. The loss of control of these processes is a hallmark of cancer.

The cell cycle is split up into four major phases based on the events unfolding in the cell. During the first gap phase (G1) the proteins are produced that are essential for DNA replication. The genetic information is then being replicated during the synthesis (S) phase. In the second gap phase (G2) all the components that are necessary for the separation of the duplicated DNA during the subsequent mitosis (M phase). Cells that are not actively dividing are considered to be in a quiescent state in the resting phase G0.

Cell division is necessary for life, but unregulated division is dangerous and counterproductive. Therefore, the cell has an impetus for maintaining tight regulatory control over how and when division takes place. There are two major checkpoints in the cell cycle. The first choke-point the cell must pass is between the G1 and S phase. A second opportunity for arrest is provided between G2 and M phases. Once DNA replication has been initiated, it must be finished. Therefore, the major checkpoint in the cell cycle is the restriction (R) point between G1 and S phases, prior to DNA duplication, at which the cycle progresses depending on mitogenic or inhibitory factors such as DNA damage and signals from various signaling pathways.

Progression from one phase to another is controlled by cyclin dependent kinases (CDK) and their activators, cyclins. Latter proteins are unstable and their cellular concentration cycles throughout the cell cycle. Accordingly, specific cyclin-CDK complexes persist in an active form for a very short period of time after translation, and are then degraded or inactivated by the time that particular phase of the cell cycle completes. Activation of specific cyclin-CDK complexes are characteristic for the different cell cycle phases, and drive production of specific molecules associated with, and necessary for that phase of division. Additional levels of dynamic control are also provided by CDK inhibitors, which block CDK function even in the presence of their requisite cyclin.

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Cyclin Dependent Kinase

CDK1 (Cyclin-Dependent Kinase 1):

The protein encoded by this gene is a member of the Ser/Thr protein kinase family. This protein is a catalytic subunit of the highly conserved protein kinase complex known as M-phase promoting factor (MPF), which is essential for G1/S and G2/M phase transitions of eukaryotic cell cycle. Mitotic cyclins stably associate with this protein and function as regulatory subunits. The kinase activity...   More...

CDK2 (Cyclin-Dependent Kinase 2):

The protein encoded by this gene is a member of the Ser/Thr protein kinase family. This protein kinase is highly similar to the gene products of S. cerevisiae cdc28, and S. pombe cdc2. It is a catalytic subunit of the cyclin-dependent protein kinase complex, whose activity is restricted to the G1-S phase, and essential for cell cycle G1/S phase transition. This protein associates with and...   More...

CDK4 (Cyclin-Dependent Kinase 4):

CDK6 (Cyclin-Dependent Kinase 6):

Antigens in this category:
CDK2AP2 (Cyclin-Dependent Kinase 2 Associated Protein 2): CDK2AP2 antibodies CDK2AP2 ELISA Kits CDK2AP2 Proteins
CDK3 (Cyclin-Dependent Kinase 3): CDK3 antibodies CDK3 ELISA Kits CDK3 Proteins
CDKL3 (Cyclin-Dependent Kinase-Like 3): CDKL3 antibodies   CDKL3 Proteins
CDK5 (Cyclin-Dependent Kinase 5): CDK5 antibodies CDK5 ELISA Kits CDK5 Proteins
CDK7 (Cyclin-Dependent Kinase 7): CDK7 antibodies CDK7 ELISA Kits CDK7 Proteins
CDK8 (Cyclin-Dependent Kinase 8): CDK8 antibodies CDK8 ELISA Kits CDK8 Proteins
CDK9 (Cyclin-Dependent Kinase 9): CDK9 antibodies CDK9 ELISA Kits CDK9 Proteins


CCNB1 - Cyclin B1

The protein encoded by this gene is a regulatory protein involved in mitosis. The gene product complexes with p34(cdc2) to form the maturation-promoting factor (MPF). Two alternative transcripts have been found, a constitutively expressed transcript and a cell cycle-regulated transcript, that is expressed predominantly during G2/M phase. The different transcripts result from the use of...   More...

CCNE1 - Cyclin E1

The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK kinases. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. This cyclin forms a complex...   More...

CCNB2 - Cyclin B2

CCNE2 - Cyclin E2

Antigens in this category:

G1-S Checkpoint

CDC25A (Cell Division Cycle 25 Homolog A (S. Pombe)):

CDC25A is a member of the CDC25 family of phosphatases. CDC25A is required for progression from G1 to the S phase of the cell cycle. It activates the cyclin-dependent kinase CDC2 by removing two phosphate groups. CDC25A is specifically degraded in response to DNA damage, which prevents cells with chromosomal abnormalities from progressing through cell division. CDC25A is an oncogene, although...   More...

CDKN2B (Cyclin-Dependent Kinase Inhibitor 2B (p15, Inhibits CDK4)):

CDKN1A (Cyclin-Dependent Kinase Inhibitor 1A (p21, Cip1)):

Antigens in this category:
FOXO1 (Forkhead Box O1): FOXO1 antibodies FOXO1 ELISA Kits FOXO1 Proteins
FOXO3 (Forkhead Box O3): FOXO3 antibodies FOXO3 ELISA Kits FOXO3 Proteins
FOXO4 (Forkhead Box O4): FOXO4 antibodies FOXO4 ELISA Kits FOXO4 Proteins
SMAD2 (SMAD, Mothers Against DPP Homolog 2): SMAD2 antibodies SMAD2 ELISA Kits SMAD2 Proteins
SMAD3 (SMAD, Mothers Against DPP Homolog 3): SMAD3 antibodies SMAD3 ELISA Kits SMAD3 Proteins
SMAD4 (SMAD Family Member 4): SMAD4 antibodies SMAD4 ELISA Kits SMAD4 Proteins
BMI1 (BMI1 Polycomb Ring Finger Oncogene): BMI1 antibodies BMI1 ELISA Kits BMI1 Proteins
MNAT1 (Menage A Trois Homolog 1, Cyclin H Assembly Factor (Xenopus Laevis)): MNAT1 antibodies MNAT1 ELISA Kits MNAT1 Proteins
CDC25B (Cell Division Cycle 25 Homolog B (S. Pombe)): CDC25B antibodies CDC25B ELISA Kits CDC25B Proteins
CDC25C (Cell Division Cycle 25 Homolog C (S. Pombe)): CDC25C antibodies CDC25C ELISA Kits CDC25C Proteins
RASGRF1 (Ras Protein-Specific Guanine Nucleotide-Releasing Factor 1): RASGRF1 antibodies RASGRF1 ELISA Kits RASGRF1 Proteins
CDKN2C (Cyclin-Dependent Kinase Inhibitor 2C (p18, Inhibits CDK4)): CDKN2C antibodies CDKN2C ELISA Kits CDKN2C Proteins
CDKN2D (Cyclin-Dependent Kinase Inhibitor 2D (p19, Inhibits CDK4)): CDKN2D antibodies   CDKN2D Proteins
CDKN1A (Cyclin-Dependent Kinase Inhibitor 1A (p21, Cip1)): CDKN1A antibodies CDKN1A ELISA Kits CDKN1A Proteins
CDKN1B (Cyclin-Dependent Kinase Inhibitor 1B (p27, Kip1)): CDKN1B antibodies CDKN1B ELISA Kits CDKN1B Proteins
CDKN1C (Cyclin-Dependent Kinase Inhibitor 1C (p57, Kip2)): CDKN1C antibodies CDKN1C ELISA Kits CDKN1C Proteins
MYC - C-MYC: MYC antibodies MYC ELISA Kits MYC Proteins


RB1 - Retinoblastoma 1

The protein encoded by this gene is a negative regulator of the cell cycle and was the first tumor suppressor gene found. The encoded protein also stabilizes constitutive heterochromatin to maintain the overall chromatin structure. The active, hypophosphorylated form of the protein binds transcription factor E2F1. Defects in this gene are a cause of childhood cancer retinoblastoma (RB), bladder...   More...

E2F1 (E2F Transcription Factor 1):

The protein encoded by this gene is a member of the E2F family of transcription factors. The E2F family plays a crucial role in the control of cell cycle and action of tumor suppressor proteins and is also a target of the transforming proteins of small DNA tumor viruses. The E2F proteins contain several evolutionally conserved domains found in most members of the family. These domains include a...   More...
Antigens in this category:
E2F2 (E2F Transcription Factor 2): E2F2 antibodies E2F2 ELISA Kits E2F2 Proteins
E2F4 (E2F Transcription Factor 4, P107/p130-Binding): E2F4 antibodies   E2F4 Proteins
TFDP1 - DP1: TFDP1 antibodies   TFDP1 Proteins
TFDP2 - DP2: TFDP2 antibodies   TFDP2 Proteins
RBL1 - p107: RBL1 antibodies RBL1 ELISA Kits RBL1 Proteins
RBL2 - p130: RBL2 antibodies RBL2 ELISA Kits RBL2 Proteins

G2-M Checkpoint

CHEK1 (Checkpoint Kinase 1):

CHEK2 (Checkpoint Kinase 2):

Antigens in this category:
MNAT1 (Menage A Trois Homolog 1, Cyclin H Assembly Factor (Xenopus Laevis)): MNAT1 antibodies MNAT1 ELISA Kits MNAT1 Proteins
CDC25A (Cell Division Cycle 25 Homolog A (S. Pombe)): CDC25A antibodies CDC25A ELISA Kits CDC25A Proteins
CDC25B (Cell Division Cycle 25 Homolog B (S. Pombe)): CDC25B antibodies CDC25B ELISA Kits CDC25B Proteins
CDC25C (Cell Division Cycle 25 Homolog C (S. Pombe)): CDC25C antibodies CDC25C ELISA Kits CDC25C Proteins
RASGRF1 (Ras Protein-Specific Guanine Nucleotide-Releasing Factor 1): RASGRF1 antibodies RASGRF1 ELISA Kits RASGRF1 Proteins
WEE1 (WEE1 Homolog (S. Pombe)): WEE1 antibodies WEE1 ELISA Kits WEE1 Proteins
MYT1 (Myelin Transcription Factor 1): MYT1 antibodies MYT1 ELISA Kits MYT1 Proteins
PLK1 (Polo-Like Kinase 1):      
PPM1D (Protein Phosphatase, Mg2+/Mn2+ Dependent, 1D): PPM1D antibodies   PPM1D Proteins
GADD45A (Growth Arrest and DNA-Damage-Inducible, alpha): GADD45A antibodies GADD45A ELISA Kits GADD45A Proteins
GADD45B (Growth Arrest and DNA-Damage-Inducible, beta): GADD45B antibodies   GADD45B Proteins
GADD45G (Growth Arrest and DNA-Damage-Inducible, gamma): GADD45G antibodies GADD45G ELISA Kits GADD45G Proteins
MDM4 - MDM4-binding Protein: MDM4 antibodies MDM4 ELISA Kits MDM4 Proteins
BRCA1 (Breast Cancer 1): BRCA1 antibodies BRCA1 ELISA Kits BRCA1 Proteins
RBBP8 - Retinoblastoma Binding Protein 8: RBBP8 antibodies   RBBP8 Proteins
HIPK2 (Homeodomain Interacting Protein Kinase 2): HIPK2 antibodies HIPK2 ELISA Kits HIPK2 Proteins
TOP2A - Topoisomerase II alpha: TOP2A antibodies TOP2A ELISA Kits TOP2A Proteins
TERF1 - TRF1: TERF1 antibodies TERF1 ELISA Kits TERF1 Proteins
TERF2 - TRF2: TERF2 antibodies TERF2 ELISA Kits TERF2 Proteins
TINF2 (TIN2): TINF2 antibodies TINF2 ELISA Kits TINF2 Proteins
TPP1 (Tripeptidyl Peptidase I): TPP1 antibodies TPP1 ELISA Kits TPP1 Proteins
POT1 (Protection of Telomeres 1 Homolog (S. Pombe)): POT1 antibodies POT1 ELISA Kits POT1 Proteins
TERF2IP - RAP1: TERF2IP antibodies TERF2IP ELISA Kits TERF2IP Proteins
AURKA - Aurora A: AURKA antibodies AURKA ELISA Kits AURKA Proteins
CDKN1A (Cyclin-Dependent Kinase Inhibitor 1A (p21, Cip1)): CDKN1A antibodies CDKN1A ELISA Kits CDKN1A Proteins
MDM2 (Mdm2, p53 E3 Ubiquitin Protein Ligase Homolog (Mouse)): MDM2 antibodies MDM2 ELISA Kits MDM2 Proteins

M Phase

INCENP (Inner Centromere Protein Antigens 135/155kDa):

In mammalian cells, 2 broad groups of centromere-interacting proteins have been described: constitutively binding centromere proteins and 'passenger,' or transiently interacting, proteins (reviewed by Choo, 1997). The constitutive proteins include CENPA (centromere protein A\; MIM 117139), CENPB (MIM 117140), CENPC1 (MIM 117141), and CENPD (MIM 117142). The term 'passenger proteins' encompasses...   More...
Antigens in this category:
AURKB - Aurora Kinase B: AURKB antibodies AURKB ELISA Kits AURKB Proteins
AURKC - Aurora Kinase C: AURKC antibodies   AURKC Proteins
CDCA8 (Cell Division Cycle Associated 8): CDCA8 antibodies CDCA8 ELISA Kits CDCA8 Proteins
BIRC5 (Baculoviral IAP Repeat-Containing 5): BIRC5 antibodies BIRC5 ELISA Kits BIRC5 Proteins
EPR1 (Early-Phytochrome-Responsive1):      

CSN Complex

GPS1 (G Protein Pathway Suppressor 1):

COPS6 (COP9 Constitutive Photomorphogenic Homolog Subunit 6 (Arabidopsis)):

Antigens in this category:
COPS2 - COP9 Constitutive Photomorphogenic Homolog Subunit 2 (Arabidopsis):     COPS2 Proteins
COPS3 (COP9 Constitutive Photomorphogenic Homolog Subunit 3 (Arabidopsis)): COPS3 antibodies   COPS3 Proteins
COPS4 (COP9 Constitutive Photomorphogenic Homolog Subunit 4 (Arabidopsis)): COPS4 antibodies   COPS4 Proteins
COPS5 (COP9 Constitutive Photomorphogenic Homolog Subunit 5 (Arabidopsis)): COPS5 antibodies COPS5 ELISA Kits COPS5 Proteins
COPS7A (COP9 Constitutive Photomorphogenic Homolog Subunit 7A (Arabidopsis)): COPS7A antibodies   COPS7A Proteins
COPS7B (COP9 Constitutive Photomorphogenic Homolog Subunit 7B (Arabidopsis)): COPS7B antibodies   COPS7B Proteins
COPS8 (COP9 Constitutive Photomorphogenic Homolog Subunit 8 (Arabidopsis)): COPS8 antibodies   COPS8 Proteins

SCF Complex

CUL1 - Cullin 1

Core component of multiple cullin-RING-based SCF (SKP1- CUL1-F-box protein) E3 ubiquitin-protein ligase complexes, which mediate the ubiquitination of proteins involved in cell cycle progression, signal transduction and transcription. In the SCF complex, serves as a rigid scaffold that organizes the SKP1-F-box protein and RBX1 subunits. May contribute to catalysis through positioning of the...   More...
Antigens in this category:
SKP1 (S-Phase Kinase-Associated Protein 1): SKP1 antibodies SKP1 ELISA Kits SKP1 Proteins
RBX1 (Ring-Box 1, E3 Ubiquitin Protein Ligase): RBX1 antibodies   RBX1 Proteins
BTRC (beta-Transducin Repeat Containing): BTRC antibodies BTRC ELISA Kits BTRC Proteins

DREAM complex

RBL1 - p107

RBL2 - p130

E2F4 (E2F Transcription Factor 4, P107/p130-Binding):


Antigens in this category:
TFDP2 - DP2: TFDP2 antibodies   TFDP2 Proteins
TFDP3 (Transcription Factor Dp Family, Member 3): TFDP3 antibodies    
LIN9 (Lin-9 Homolog (C. Elegans)): LIN9 antibodies   LIN9 Proteins
LIN37 (Lin-37 Homolog (C. Elegans)): LIN37 antibodies   LIN37 Proteins
LIN54 (Lin-54 Homolog (C. Elegans)): LIN54 antibodies   LIN54 Proteins
RBBP4 - Retinoblastoma Binding Protein 4: RBBP4 antibodies RBBP4 ELISA Kits RBBP4 Proteins
MYBL1 (Myb-Like Protein 1): MYBL1 antibodies MYBL1 ELISA Kits MYBL1 Proteins
MYBL2 (V-Myb Myeloblastosis Viral Oncogene Homolog (Avian)-Like 2): MYBL2 antibodies MYBL2 ELISA Kits MYBL2 Proteins