Genetic approaches to studying peroxisome biogenesis.

How proteins are imported into peroxisomes is a question attracting considerable interest at present. Peroxisomal proteins, including the integral membrane proteins of the membrane bounding the peroxisome, are synthesized on free cytoplasmic ribosomes. They assemble post-translationally into pre-existing peroxisomes. New peroxisomes are believed to form exclusively by division of old ones. Few molecular details of this process have been elucidated so far, but genetic approaches are now beginning to identify the proteins catalysing peroxisome assembly.