https://www.laboratorynotes.com/cell/ Thu, 27 Aug 2026 16:21:41 +0000 hourly 1 https://wordpress.org/?v=7.1 https://www.laboratorynotes.com/cell/#comment-80983 Thu, 27 Aug 2026 16:21:41 +0000 https://www.laboratorynotes.com/?p=15535#comment-80983 […] Cells use two major pathways for protein degradation: the ubiquitin–proteasome system (UPS) and the autophagy-lysosome pathway. The UPS is responsible for degrading short‑lived, regulatory, or misfolded proteins. In this pathway, proteins are tagged with ubiquitin molecules through a series of enzymatic reactions involving E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin ligase) enzymes. This ubiquitin tag acts as a signal that directs the protein to the proteasome, a large multi‑subunit complex that unfolds and breaks down proteins into small peptides. The UPS provides rapid and selective degradation, making it essential for processes such as cell‑cycle control, transcriptional regulation, and removal of damaged proteins. […]

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