Which protein is required for peroxisomal membrane biogenesis?
De novo biogenesis and growth peroxisomal membrane depends targeted insertion peroxisomal membrane proteins PMPs specialized machinery distinct matrix pathway. PMPs including docking Pex14 Pex13 fission factors Pex11 isoforms transporters ABCD1-3 synthesized free cytosolic ribosomes containing hydrophobic transmembrane domains aggregation prone requiring chaperoning. Cytosolic receptor chaperone Pex19 farnesylated C-terminal CAAX box binds PMPs hydrophobic groove preventing aggregation maintaining solubility delivering peroxisomal membrane docking platform. Targeting essential factors Pex3 42 kDa integral membrane short lumenal N-terminus docking anchor Pex19-PMP complex, and Pex16 integral membrane two transmembrane helices recruits Pex3 ER-derived pre-peroxisomal vesicles stabilizes growth. Current model Pex3 Pex16 first insert ER via Sec61 segregate subdomain forming pre-peroxisomal vesicles budding Pex19 dependent mature functional peroxisomes importing matrix enzymes. Pex5 Pex7 soluble matrix import receptors PTS1 PTS2 luminal proteins not membrane biogenesis, Tom20 Tom22 mitochondrial outer receptors presequences, Hsp70 Hsp90 general cytosolic folding chaperones unrelated specific PMP insertion. Human cells lacking Pex3 or Pex16 absence detectable membranes microscopy PMPs mislocalized mitochondria rapidly degraded clinical Zellweger illustrating foundational role membrane formation identity maintenance and disease.
Ref: Distel et al., Annu Rev Biochem: Pex3 and Pex16 essential for peroxisomal membrane biogenesis.