Proteasome Markers

The proteasome is a large, barrel-shaped protein complex responsible for degrading damaged, misfolded, or otherwise dispensable proteins through its proteolytic activity. Structurally, the proteasome consists of a catalytic 20S core particle supported by the 19S regulatory particle. In addition to scaffolding the core particle, the 19S particle has important roles in proteasome assembly as well as protein substrate recognition. The 20S core particle is composed of four hetero-heptameric rings. The two outer rings contain proteasome subunit alpha-type (PSMA) proteins while the two inner rings contain proteasome subunit beta-type (PSMB) proteins. The outer α rings assist in substrate recognition but primarily adopt a structural role creating a gate which blocks entry into the inner catalytic core. In this way, PSMA1 detection can be used as a proteasomal marker for complex integrity and substrate recognition capability. Each of the seven β subunits possess distinct activities which contribute towards the proteolytic capacity of the core. For example, PSMB5 is used as a marker to evaluate chymotrypsin-like peptide bond cleavage while PSMB6 and PSMB7 exhibit trypsin-like and caspase-like activities respectively. The cooperative action of β subunits ensures proteins are degraded efficiently through regular cleavage along the polypeptide sequence. The 19S regulatory particle consists of non-ATPase (PSMD7, RPN2, PSMD1) and ATPase subunits (PSMC1). PSMC1, an ATPase subunit, contributes to the unfolding and translocation of ubiquitinated substrates. 19S subunits act as important proteasome markers as they inform complex structure and dynamics. By monitoring the abundance and modifications of PSMD7, RPN2, and PSMD1, researchers may assess the composition and regulation of the 19S particle. The diverse functions of proteasome markers in substrate recognition, catalysis, and unfolding enable researchers to unravel the intricacies of targeted protein degradation to maintain cellular homeostasis. We offer a range of antibodies against proteasomal markers including Proteasome 19S S4 antibodies, PSMB5 antibodies, PSMD1 antibodies, and PSMD7 antibodies, that are validated across multiple applications and cover various antibody types, clonalities, host species, and conjugates. These reagents can be used to probe multiple cellular processes which rely on ubiquitin-mediated proteasome-dependent degradation, including: shock responses; antigen presentation; transcription; cell signalling; and cell surface protein turnover.