Category: Lab Notes: Cell Biology

Cells form the foundation of all living organisms, and cell theory explains their universal role in structure, function, and continuity of life. This article explores the origins, principles, and significance of cell theory, highlighting how it shapes modern biological understanding.

The term cell is fundamental to modern biology, yet its origin lies in a simple visual observation made more than…

The ubiquitin–proteasome system is the primary pathway for selective protein degradation in eukaryotic cells. This article explains its structure, function, and importance in cellular regulation and disease.

The proteasome is the cell’s primary protein degradation machinery, responsible for eliminating damaged and regulatory proteins. This comprehensive guide covers its structure, the ubiquitin-tagging process, its role in neurodegeneration and cancer, and the development of proteasome inhibitors like bortezomib for cancer therapy.

RING finger ubiquitin ligases are the largest class of E3 enzymes in the ubiquitin–proteasome system, defined by a zinc‑binding cross‑brace RING domain that positions E2~Ub for direct ubiquitin transfer. They regulate essential cellular processes including cell cycle progression, DNA repair, immunity, and neuronal function. Dysregulation of RING and RBR ligases such as MDM2 and Parkin contributes to cancer and neurodegeneration, while modern PROTAC therapeutics harness CRL4^CRBN and CRL2^VHL complexes to redirect ubiquitination toward disease‑associated proteins.