Involved in peroxisomal proliferation. Promotes peroxisomal duplication, aggregation or elongation without fission. Homooligomer. Interacts with ARC5 and FIS1B on peroxisomes. Expressed in leaves and developing siliques. Up-regulated during sensecence. Down-regulated in seedlings by transition from dark to light. Can complement the yeast pex11 null mutant. Belongs to the peroxin-11 family.