TAZ1 encodes a mitochondrial lyso-phosphatidylcholine acyltransferase (3) involved in the remodeling of cardiolipin, a mitochondrial inner and outer membrane phospholipid required for normal respiratory function. Cardiolipin, synthesized by the cardiolipin biosynthesis pathway, has an unique structure with two phosphatidyl moieties linked by a glycerol bridge, giving the molecule four fatty acyl chains and two phosphate groups (2).

The taz1 null mutant accumulates monolyso-cardiolipin, an intermediate in the cardiolipin biosynthesis pathway and also exhibits other phospholipid defects such as increased phosphatidylethanolamine and phosphatidylserine levels and decreased levels of phosphatidic acid. These phopholipid defects are similar to those observed in Barth syndrome, a disease associated with the human homolog of Taz1p, Tafazzin (2, 4). Barth Syndrome is an inherited X-linked recessive disease that is often fatal in childhood and is characterized by skeletal myopathy, neutropenia and abnormal mitochondria.

The taz1 null mutations also affect the stable formation of supercomplexes between Complex III and Complex IV of the respiratory chain, resulting in respiratory defects at elevated or decreased temperatures (5).

Last updated: 2006-11-20