LACTB | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | LACTB , G24, MRPL56, lactamase beta | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 608440; MGI: 1933395; HomoloGene: 12755; GeneCards: LACTB; OMA:LACTB - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Serine beta-lactamase-like protein LACTB, mitochondrial is an enzyme that in humans is encoded by the LACTB gene. [5] [6] This gene encodes a 54 kDa protein sharing significant sequence similarity to serine proteases of the penicillin binding protein and beta-lactamase superfamily occurring in bacteria. [7] It is involved in the regulation of the metabolic circuitry. A causal association has been found between LACTB and obesity. [8] In breast cancer, LACTB has a tumor suppressor function by modulating lipid metabolism. [9]
The LACTB gene is located at chromosome 15q22.1, consisting of 8 exons. Alternative splicing results in multiple transcript variants encoding different protein isoforms.
LACTB shares sequence similarity to the beta-lactamase/penicillin-binding protein family of serine proteases that are involved in bacterial cell wall metabolism. The N-terminal 97 amino acid segment of LACTB does not form part of the conserved penicillin-binding protein domain and may therefore be responsible for organelle targeting. [7] [10]
LACTB is widely expressed in different mammalian tissues, with the predominant expression in human skeletal muscle. It localizes in the mitochondrial intermembrane space. [10] LACTB can polymerize into stable filaments occupying the mitochondrial intermembrane space. These filaments are speculated to play a role in submitochondrial organization and therefore possibly affect mitochondrial metabolon organization. [10]
It has been found LACTB could cause obesity through gene co-expression analysis based on data integrated from multiple sources. This has been validated in vivo through LACTB overexpression in transgenic mice, which resulted in an obese phenotype. [8] LACTB has also been identified to be a tumor suppressor through its effect on mitochondrial phospholipid metabolism and modulation of cell differentiation state. [11]