Ubiquitin conjugating enzymes- also known as E2 enzymes- play intermediary roles in the ubiquitin-proteasome system (UPS) and are essential for maintaining cellular protein homeostasis. These enzymes facilitate the transfer of ubiquitin molecules to target proteins, marking them for degradation or modulating their functions through various ubiquitin chain linkages. Whilst E1 enzymes activate ubiquitin and E3 enzymes facilitate the transfer of ubiquitin from E2 enzymes to the target protein, E2 enzymes serve as intermediaries in the transfer of ubiquitin from E1 to E3 and, in some cases, directly to the target protein. A critical E2 enzyme is UBE2D, also known as UBCH5. UBE2D is involved in ubiquitin conjugation for protein degradation through the 26S proteasome. It functions with E1 ubiquitin-activating enzymes and E3 ubiquitin ligases to transfer ubiquitin to substrate proteins. UBE2D, along with its family members, contributes to the tagging of misfolded or damaged proteins with polyubiquitin chains, targeting them for degradation. This process is vital for maintaining cellular quality control and preventing the accumulation of toxic protein aggregates, such as those seen in neurodegenerative diseases like Alzheimer's and Parkinson's. An example of an E2 enzyme involved in selective autophagy is UBE2QL1. Autophagy is the cellular process that eliminates damaged organelles and protein aggregates by delivering them to lysosomes for degradation. UBE2QL1 plays a role in the ubiquitylation of cargo proteins that are destined for autophagic clearance. For example, it participates in the ubiquitylation of p62/SQSTM1, a scaffold protein that links cargo to the autophagic machinery, promoting the engulfment of cargo by autophagosomes and subsequent lysosomal degradation. Another distinct E2 enzyme is UBC9, also known as UBE2I, responsible for the conjugation of small ubiquitin-like modifier (SUMO) proteins to target substrates and critical for DNA repair, transcription, and protein localization. For example, in DNA repair, UBC9 mediates the SUMOylation of various repair factors, such as PCNA, which enhances their recruitment to DNA damage sites, facilitating efficient repair. UBE2K (also known as HIP2) is also involved in the ubiquitylation of substrates. This E2 enzyme functions in the N-end rule pathway, where it conjugates ubiquitin to proteins with specific N-terminal amino acids, marking them for proteasomal degradation. UBE2K's activity is crucial for regulating the stability of proteins involved in various cellular processes, including cell cycle progression and apoptosis. One example is the regulation of the cell cycle inhibitor p27Kip1, which is targeted for degradation by UBE2K-dependent ubiquitylation during cell cycle progression. Additionally, UBE2E family members (UBE2E1, UBE2E2, and UBE2E3) are notable for their role in the ubiquitylation of cell cycle regulators. They participate in the ubiquitylation and subsequent degradation of cyclin-dependent kinase inhibitors (CDKIs), such as p21Cip1 and p27Kip1, promoting cell cycle progression. Dysregulation of these E2 enzymes can therefore lead to abnormal cell proliferation and contribute to cancer development. Thus, E2 enzymes are critical components of the ubiquitin-proteasome system and play diverse roles in regulating cellular processes. Each E2 enzyme has specific substrates and functions, ranging from protein degradation to post-translational modifications. We offer a large product catalogue of research reagents for studying E2 ubiquitin conjugating enzymes, including Cdc34 antibodies, UBE2C antibodies, and Ube2B antibodies. Explore our full E2 ubiquitin conjugating enzymes product range below and discover more, for less.