Category: Database

pRb is a major tumour‑suppressor that governs the G1–S transition by restraining E2F transcription factors and maintaining a repressive chromatin state. When pRb becomes hyperphosphorylated, cells commit to DNA replication. Loss of pRb function leads to uncontrolled proliferation, replication stress and genomic instability, making it a key player in cancer development.

Cdh1 is a major activator of the APC/C complex, responsible for mitotic exit, G1 maintenance and replication licensing. By degrading Cyclin B, Aurora A, Plk1 and Geminin, Cdh1 prevents premature S‑phase entry and maintains genomic stability. Its dysregulation contributes to replication stress, chromosomal instability and cancer development.

Cdc20 is a key activator of the APC/C complex, initiating the metaphase‑to‑anaphase transition by promoting securin and Cyclin B degradation. Regulated by checkpoint proteins such as Mad2 and BubR1, Cdc20 safeguards chromosome segregation, while its dysregulation contributes to aneuploidy and cancer progression.

p19^INK4d is a key CDK4/6 inhibitor that stabilises cell‑cycle exit during differentiation and responds to DNA damage. Its roles in growth control and tumour suppression make it an essential regulator of the G₁ checkpoint.

p15^INK4b is a key CDK4/6 inhibitor activated by TGF‑β signalling. Its roles in growth inhibition, differentiation, and tumour suppression make it an essential regulator of the G₁ checkpoint.

p16^INK4a is a tumour‑suppressor protein that inhibits CDK4/6, blocks Rb phosphorylation, and enforces G₁ arrest. Its roles in senescence, ageing, and cancer make it a central regulator of cell‑cycle control.

p18^INK4c is a key CDK4/6 inhibitor that stabilises cell‑cycle exit during differentiation. Its roles in growth control, tissue homeostasis, and tumour suppression make it an essential regulator of the G₁ checkpoint.

p57^Kip2 is a key CDK inhibitor with major roles in development, differentiation, and cell‑cycle restraint. Its unique imprinting and tissue‑specific expression make it essential for balancing growth and maturation.

p27^Kip1 is a key CDK inhibitor that prevents premature entry into S phase. Its regulation by mitogenic signalling and degradation by SCF^Skp2 make it essential for cell‑cycle control, quiescence, and tumour suppression.

p21^WAF1 is a key CDK inhibitor that halts the cell cycle in response to DNA damage. By regulating cyclin–CDK complexes and interacting with PCNA, p21 maintains genomic stability and prevents the propagation of mutations.

Cullins are core scaffold proteins of Cullin‑RING ligases, enabling targeted protein degradation through the ubiquitin–proteasome system. Their roles in cell‑cycle control, signalling, and DNA‑damage responses make them essential regulators of cellular stability.

F‑box proteins are key components of the SCF complex, providing substrate specificity for ubiquitin‑mediated protein degradation. Their roles in cell‑cycle control, signalling, and protein homeostasis make them essential regulators of cellular physiology.

SYCP2 is a meiosis‑specific protein that forms the lateral elements of the synaptonemal complex. Its interaction with SYCP3 is essential for chromosome pairing, recombination, and fertility.

Tryptophan is an essential amino acid with important roles in protein synthesis, neurotransmitter production, immune regulation, and metabolism. It serves as a precursor for serotonin and melatonin and is also metabolized through the kynurenine pathway to produce several biologically active compounds.