PEX19 is a predominantly cytosolic chaperone and import receptor for class 1 peroxisomal membrane proteins

JM Jones, JC Morrell, SJ Gould - The Journal of cell biology, 2004 - rupress.org
JM Jones, JC Morrell, SJ Gould
The Journal of cell biology, 2004rupress.org
Integral peroxisomal membrane proteins (PMPs) are synthesized in the cytoplasm and
imported posttranslationally. Here, we demonstrate that PEX19 binds and stabilizes newly
synthesized PMPs in the cytosol, binds to multiple PMP targeting signals (mPTSs), interacts
with the hydrophobic domains of PMP targeting signals, and is essential for PMP targeting
and import. These results show that PEX19 functions as both a chaperone and an import
receptor for newly synthesized PMPs. We also demonstrate the existence of two PMP import …
Integral peroxisomal membrane proteins (PMPs) are synthesized in the cytoplasm and imported posttranslationally. Here, we demonstrate that PEX19 binds and stabilizes newly synthesized PMPs in the cytosol, binds to multiple PMP targeting signals (mPTSs), interacts with the hydrophobic domains of PMP targeting signals, and is essential for PMP targeting and import. These results show that PEX19 functions as both a chaperone and an import receptor for newly synthesized PMPs. We also demonstrate the existence of two PMP import mechanisms and two classes of mPTSs: class 1 mPTSs, which are bound by PEX19 and imported in a PEX19-dependent manner, and class 2 mPTSs, which are not bound by PEX19 and mediate protein import independently of PEX19.
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