Principles of peroxisome proliferation in fungi

PhD ceremony: Mr. L. Opalinski, 14.30 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Principles of peroxisome proliferation in fungi

Promotor(s): prof. I.J. van der Klei, prof. M. Veenhuis

Faculty: Mathematics and Natural Sciences

Lukasz Opalinski studied the contribution of Pex11 family members (Pex11, Pex11B and Pex11C) as well as Pex16 and Pex3 in peroxisome biogenesis in the filamentous fungus Penicillium chrysogenum.

Eukaryotic cells contain membrane enclosed compartments named organelles. Peroxisomes are single membrane bound organelles that are characterized by the large diversity of functions that they can perform. Peroxisomes may behave as autonomous organelles that grow, divide and are inherited, ensuring the continuous presence of these organelles in newly formed cells. The peroxisome proliferation machinery is composed of peroxisome specific factors (mainly Pex11) and proteins that besides peroxisome fission also control division of mitochondria (Fis-1, Dnm1).

Based on his data Opalinski proposes that Pex11 is a morphogenic protein that by induction of high membrane curvature causes tubulation of peroxisomes. In addition, he demonstrated that Pex11 is also involved in attraction/regulation of function of Dnm1.

Opalinski identified a novel peroxisomal membrane protein, Pex14/17, that is present only in filamentous fungi. His data suggest that Pex14/17 is a specialized form of yeast Pex17 that participates in protein import into peroxisomes, but is also important for production of secondary metabolites (like penicillin) in P. chrysogenum.