Cyclin A1

Cyclin A1 is a member of the highly conserved cyclin family that is characterized by a dramatic periodicity in protein abundance, and belongs to the A-type cyclin subfamily. The mammalian A-type cyclin family consists of two members: cyclin A1 and cyclin A2. Different cyclins exhibit distinct expression. Cyclin A1 is expressed in mice exclusively in the germ cell lineage and high rate of cyclinA1 is found in human testis and certain myeloid leukaemia cells. Cyclin A1 is primarily function in the control of meiosis. It serves as regulator subunits binding to cyclin-dependent kinase 1 (Cdk1) and cyclin-dependent kinase 2 (Cdk2), which give two different kinase activities, one appearing in S phase, the other in G2. Through this, cyclin A1 operate the entry and progression in cell cycle. High frequency of cyclin A1 overexpression has been observed in acute myelocytic leukemias, especially those that are at the promyelocyte and myeloblast stages of development.

Cyclin A1 Related Areas

Cancer>>Cell Cycle>>Cyclin>>Cyclin A1/CCNA1

Cyclin A1 Alternative Names

CCNA1, cyclin-A1 [Homo sapiens]

Ccna1, MGC159139, cyclin-A1 [Mus musculus]

Summaries for Cyclin A1

Entrez Gene summary for Cyclin A1:

Encodes a core cell cycle gene involved in meiosis II during microsporogenesis. Recessive mutants exhibit delayed and asynchronous meiosis in pollen mother cell populations and uncoordinated nuclear division and cytokinesis resulting in dyad microspores.

OMIM - description for Cyclin A1:

The kinase activity of the CDK2 (116953)-cyclin A complex, which peaks at the G1/S transition of the cell cycle, is required for the cell to enter S phase. Cyclin A also forms a complex with CDC2 (116940), whose activity peaks at the G2/M transition, and the kinase activity of CDC2-cyclin A is required for the cell to enter M phase. Xenopus and mouse contain 2 cyclin A genes, cyclin A1 and cyclin A2, the homolog of human cyclin A (CCNA2; 123835). By searching an EST database with a cyclin consensus sequence, Yang et al. (1997) identified a cDNA encoding the human cyclin A1. The predicted 465-amino acid protein shares 84%, 59%, and 48% sequence identity with mouse cyclin A1, Xenopus cyclin A1, and human cyclin A, respectively. Northern blot analysis revealed that the 2.1-kb cyclin A1 mRNA was only expressed in testis and brain, with the level of expression in testis being much higher. In addition, the authors detected cyclin A1 mRNA in ML-1 and several other myeloid leukemia cell lines. The expression of cyclin A1 was differentiation- and cell cycle-regulated in ML-1 cells. Cyclin A1 protein had an apparent molecular mass of 65 kD and coimmunoprecipitated with CDK2 and showed histone H1 (see 142711) kinase activity in ML-1 cell extracts.

Wikipedia summary for Cyclin A1:

Cyclin-A1 is a protein that in humans is encoded by the CCNA1 gene. 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 division cycle. Cyclins function as activating subunits of enzymatic complex together with cyclin-dependent kinases (CDKs). Different cyclins exhibit distinct expression and degradation patterns that contribute to the temporal coordination of cell cycle events. Cyclin A1 was shown to be expressed in testis and brain, as well as in several leukemic cell lines, and is thought to primarily function in the control of meiosis. This cyclin binds both Cdk1 and Cdk2 kinases, which give two distinct kinase activities, one appearing in S phase, the other in G2, and thus regulate separate functions in cell cycle. This cyclin was found to bind to important cell cycle regulators, such as Rb family proteins, transcription factor E2F1, and the Kip/Cip family of CDK-inhibitor proteins.

Human Cyclin A1 Protein General Information

 

• Protein names: Recommended name: Cyclin-A1
• Sequence length: 465 AA.
• Sequence similarities: Belongs to the cyclin family. Cyclin AB subfamily.
• Post-translational modification: Polyubiquitinated via 'Lys-11'-linked ubiquitin by the anaphase-promoting complex (APC/C), leading to its degradation by the proteasome. Deubiquitinated and stabilized by USP37 enables entry into S phase.
• Subunit structure: Interacts with the CDK2 and the CDC2 protein kinases to form a serine/threonine kinase holoenzyme complex. The cyclin subunit imparts substrate specificity to the complex. Does not bind CDK4 and CDK5 (in vitro). The cyclin A1-CDK2 complex interacts with transcription factor E2F-1 and RB proteins. Found in a complex with CDK2, CABLES1 and CCNE1 By similarity. Interacts with INCA1 and KLHDC9
• Subcellular location: Nucleus
• Tissue specificity: Very high levels in testis and very low levels in brain. Also found in myeloid Leukemia cell lines.

General information above from UniProt

Function for Cyclin A1 Protein

UniProtKB:

May be involved in the control of the cell cycle at the G1/S (start) and G2/M (mitosis) transitions. May primarily function in the control of the germline meiotic cell cycle and additionally in the control of mitotic cell cycle in some somatic cells

Genatlas:

• regulator of cell-cycle
• G2 phase CCNA1/CDK2 controls the timing of entry into mitosis by controlling the subsequent activation of CCNB/CDK1, but also has an unexpected role in coordinating the activation of CCNB/CDK1 at the
• cell cycle regulator that has been implicated in the progression of prostate cancer
• Cyclin A1 has a meiosis-specific function

Homology for human Cyclin A1

• homolog to murine Ccna1
• homolog to ccna2