The promoter of filamentation (POF1) protein from Saccharomyces cerevisiae is an ATPase involved in the protein quality control process.
BACKGROUND
The gene YCL047C, which has been renamed promoter of filamentation gene (POF1), has recently been described as a cell component involved in yeast filamentous growth. The objective of this work is to understand the molecular and biological function of this gene.


RESULTS
Here, we report that the protein encoded by the POF1 gene, Pof1p, is an ATPase that may be part of the Saccharomyces cerevisiae protein quality control pathway. According to the results, Δpof1 cells showed increased sensitivity to hydrogen peroxide, tert-butyl hydroperoxide, heat shock and protein unfolding agents, such as dithiothreitol and tunicamycin. Besides, the overexpression of POF1 suppressed the sensitivity of Δpct1, a strain that lacks a gene that encodes a phosphocholine cytidylyltransferase, to heat shock. In vitro analysis showed, however, that the purified Pof1p enzyme had no cytidylyltransferase activity but does have ATPase activity, with catalytic efficiency comparable to other ATPases involved in endoplasmic reticulum-associated degradation of proteins (ERAD). Supporting these findings, co-immunoprecipitation experiments showed a physical interaction between Pof1p and Ubc7p (an ubiquitin conjugating enzyme) in vivo.


CONCLUSIONS
Taken together, the results strongly suggest that the biological function of Pof1p is related to the regulation of protein degradation.
Departamento de Tecnologia Bioquímico-Farmacêutica, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo - USP, São Paulo-SP, Brazil.
Iris M
IM
Costa
Tallybia H T
TH
Nasser
Marilene
M
Demasi
Rafaella M P
RM
Nascimento
Luis E S
LE
Netto
Sayuri
S
Miyamoto
Fernanda M
FM
Prado
Gisele
G
Monteiro
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D060746:Endoplasmic Reticulum-Associated Degradation; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases