Acyl-CoA oxidase, peroxisomal thiolase and dihydroxyacetone phosphate acyltransferase: aberrant subcellular localization in Zellweger syndrome

We have studied the presence and subcellular localization of peroxisomal 3-oxoacylcoenzyme A thiolase, acylcoenzyme A oxidase and acyl-CoA: dihydroxyacetonephosphate acyltransferase (DHAPAT) in fibroblasts from control subjects and patients with an inherited deficiency of peroxisomes (Zellweger syndrome), using immunofluorescence spectroscopy and density gradient centrifugation techniques. The results show that Zellweger cells contain unprocessed thiolase and unprocessed acyl-CoA oxidase which are associated with structures containing a peroxisomal integral membrane protein of 69 kDa and having a density much lower than that of normal peroxisomes. The residual DHAPAT activity present in Zellweger cells is also contained in these structures. We conclude that these structures represent defectively assembled peroxisomes which may still be capable of importing some peroxisomal proteins