PISD

PISD catalyzes the conversion of phosphatidylserine to phosphatidylethanolamine in the inner mitochondrial membrane. The encoded protein is active in phospholipid metabolism and interorganelle trafficking of phosphatidylserine.

Phosphatidylserine decarboxylase

Catalyzes the formation of phosphatidylethanolamine (PtdEtn) from phosphatidylserine (PtdSer) (PubMed:30488656, PubMed:30858161).
Plays a central role in phospholipid metabolism and in the interorganelle trafficking of phosphatidylserine.

Mitochondrial protein catabolic processManual Assertion Based On ExperimentIMP:UniProtKB
Phosphatidylethanolamine biosynthetic processManual Assertion Based On ExperimentIMP:UniProtKB
Protein autoprocessingIEA:UniProtKB-UniRule
Regulation of mitochondrion organizationManual Assertion Based On ExperimentIMP:UniProtKB

Phosphatidylserine decarboxylase beta chain
Mitochondrion inner membrane
Phosphatidylserine decarboxylase alpha chain
Mitochondrion inner membrane
Anchored to the mitochondrial inner membrane through its interaction with the integral membrane beta chain.

Liberfarb syndrome (LIBF):
An autosomal recessive multisystem disorder affecting the eye, ear, bone, and brain development. Clinical features include early-onset retinal degeneration, congenital cataracts, sensorineural hearing loss, microcephaly, intellectual disability, white matter changes, mild facial dysmorphism, and skeletal dysplasia with platyspondyly, scoliosis and short stature.

Mitochondrial matrix: 53-63
Helical: 64-82
Mitochondrial intermembrane: 83-409

Is synthesized initially as an inactive proenzyme. Formation of the active enzyme involves a self-maturation process in which the active site pyruvoyl group is generated from an internal serine residue via an autocatalytic post-translational modification. Two non-identical subunits are generated from the proenzyme in this reaction, and the pyruvate is formed at the N-terminus of the alpha chain, which is derived from the carboxyl end of the proenzyme. The autoendoproteolytic cleavage occurs by a canonical serine protease mechanism, in which the side chain hydroxyl group of the serine supplies its oxygen atom to form the C-terminus of the beta chain, while the remainder of the serine residue undergoes an oxidative deamination to produce ammonia and the pyruvoyl prosthetic group on the alpha chain. During this reaction, the Ser that is part of the protease active site of the proenzyme becomes the pyruvoyl prosthetic group, which constitutes an essential element of the active site of the mature decarboxylase.