Hansenula polymorpha Pex19p is essential for the formation of functional peroxisomal membranes.
We have cloned and characterized the Hansenula polymorpha PEX19 gene. In cells of a pex19 disruption strain (Hppex19), induced on methanol, peroxisome structures were not detectable; peroxisomal matrix proteins accumulated in the cytosol, whereas peroxisomal membrane proteins (PMPs) were mislocalized to the cytosol (Pex3p) and mitochondria (Pex14p) or strongly reduced to undetectable levels (Pex10p). The defect in peroxisome formation in Hppex19 cells was largely suppressed upon overproduction of HpPex3p or a fusion protein that consisted of the first 50 N-terminal amino acids of Pex3p and GFP. In these cells PMPs were again correctly sorted to peroxisomal structures, which also harbored peroxisomal matrix proteins. In Saccharomyces cerevisiae pex19 cells overproduction of ScPex3p led to the formation of numerous vesicles that contained PMPs but lacked the major matrix protein thiolase. Taken together, our data are consistent with a function of Pex19p in membrane protein assembly and function.
Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, P. O. Box 14, 9750 AA Haren, The Netherlands.
Marleen
M
Otzen
Uta
U
Perband
Dongyuan
D
Wang
Richard J S
RJ
Baerends
Wolf H
WH
Kunau
Marten
M
Veenhuis
Ida J
IJ
Van der Klei
D001483:Base Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000502:physiology; D007425:Intracellular Membranes; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D000074401:Peroxins; D020675:Peroxisomes / Q000648:ultrastructure*; D010843:Pichia / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology
D005656:Fungal Proteins; D008565:Membrane Proteins; C070895:PEX3 protein, S cerevisiae; D000074401:Peroxins; D029701:Saccharomyces cerevisiae Proteins