Lon protease, bacterial/eukaryotic-type (IPR004815)

Short name: Lon_bac/euk-typ

Overlapping homologous superfamilies

Family relationships


Lon protease belongs to the S16 peptidase family and is an ATP-dependent serine protease that mediates the selective degradation of mutant and abnormal proteins, as well as certain short-lived regulatory proteins. It is required for cellular homeostasis and for survival from DNA damage and developmental changes induced by stress [PMID: 17216028]. In pathogenic bacteria, it is required for the expression of virulence genes that promote cell infection [PMID: 10672180].

Lon (La) protease was the first ATP-dependent protease to be purified from E. coli [PMID: 9425059, PMID: 3042779, PMID: 8294008, PMID: 8226758]. The enzyme is a homotetramer of 87kDa subunits, with one proteolytic and one ATP-binding site per monomer, making it structurally less complex than other known ATP-dependent proteases [PMID: 3042779]. Despite this relative structural simplicity, Lon recognises its substrates directly, without delegating the task of substrate recognition to other enzymes [PMID: 3042779].

This signature defines the bacterial and eukaryotic lon proteases. This family of sequences does not include the archaeal lon homologues, IPR004663. In the eukaryotes the majority of the proteins are located in the mitochondrial matrix [PMID: 8248235, PMID: 9620272]. The yeast homologue, Pim1, is required for mitochondrial function and is constitutively expressed, but is increased after thermal stress, suggesting that Pim1 may play a role in the heat shock response [PMID: 8276800].

GO terms

Biological Process

GO:0006508 proteolysis

Molecular Function

GO:0005524 ATP binding
GO:0004176 ATP-dependent peptidase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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