May be involved in peroxisomal proliferation and may regulate peroxisomes division. May mediate binding of coatomer proteins to the peroxisomal membrane (By similarity). Promotes membrane protrusion and elongation on the peroxisomal surface. Homodimer. Heterodimer with PEX11G. Probably interacts with COPB2 and COPA. Interacts with PEX19. Interacts with FIS1. Strongly expressed in liver and at lower levels in heart, brain, kidney and testis. By ciprofibrate. Mice have no detectable defect in constitutive peroxisome division and display a normal peroxisome proliferation response when exposed to PPARalpha-activating drugs. However, they are defective in peroxisome proliferation induced by 4-phenylbutyrate (4-PBA). Belongs to the peroxin-11 family.