|
|
|
|
|
|
|
||
J. Cell Biol.,
Volume 141, Number 3, May 4, 1998 625-636
* Department of Biology, University of California, San Diego, La Jolla, California 92093-0322; and We used the dye N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenylhexatrienyl) pyridinium dibromide (FM4-64) and a fusion protein, consisting of the green fluorescent protein appended to the
peroxisomal targeting signal, Ser-Lys-Leu (SKL), to label the vacuolar membrane and the peroxisomal matrix, respectively, in living Pichia pastoris cells and followed by fluorescence microscopy the morphological
and kinetic intermediates in the vacuolar degradation of peroxisomes by microautophagy and macroautophagy. Structures corresponding to the intermediates
were also identified by electron microscopy. The kinetics of appearance and disappearance of these intermediates is consistent with a precursor-product relationship between intermediates, which form the basis of a
model for microautophagy. Inhibitors affecting different steps of microautophagy did not impair peroxisome
delivery to the vacuole via macroautophagy, although
inhibition of vacuolar proteases affected the final vacuolar degradation of green fluorescent protein (S65T
mutant version [GFP])-SKL via both autophagic pathways. P. pastoris mutants defective in peroxisome microautophagy (pag mutants) were isolated and characterized for the presence or absence of the
intermediates. These mutants, comprising 6 complementation groups, support the model for microautophagy. Our studies indicate that the microautophagic
degradation of peroxisomes proceeds via specific intermediates, whose generation and/or processing is controlled by PAG gene products, and shed light on the
poorly understood phenomenon of peroxisome homeostasis.
Pharmacological Science,
Genentech, South San Francisco, California 94080
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
