Sequestosome-1, PB1 domain (IPR034866)

Short name: PB1_p62

Overlapping homologous superfamilies


Domain relationships

  • PB1 domain (IPR000270)
    • Sequestosome-1, PB1 domain (IPR034866)


The PB1 domain is an essential part of p62 scaffold protein (alias sequestosome 1, SQSTM) involved in cell signaling, receptor internalization, and protein turnover [PMID: 17188686, PMID: 19903815]. It binds ubiquitinated substrates and aid their aggregation and degradation by macroautophagy [PMID: 20168092].

The PB1 domain is a modular domain mediating specific protein-protein interaction which play roles in many critical cell processes. A canonical PB1-PB1 interaction, which involves heterodimerization of two PB1 domains, is required for the formation of macromolecular signaling complexes ensuring specificity and fidelity during cellular signaling. The interaction between two PB1 domain depends on the type of PB1. There are three types of PB1 domains: type I which contains an OPCA motif, acidic aminoacid cluster, type II which contains a basic cluster, and type I/II which contains both an OPCA motif and a basic cluster. Interactions of PB1 domains with other protein domains have been described as noncanonical PB1-interactions. The PB1 domain module is conserved in amoebas, fungi, animals, and plants [PMID: 17726178].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.