Page 7 - F. Cell biology

PRMT1 upregulates c-Fos-mediated AP-1 activity by
regulating the stability of c-Fos via autophagy blockade

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Eunji Kim , Chaoran Song , Han Gyung Kim , Deok Jeong , Yo Han Hong , Long You , Wooram Choi , Jieun Oh and Jae Youl Cho 1
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1 Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Republic of Korea
BACKGROUND AIM
AP-1 is transcriptional factor to regulate diverse cellular To explore the regulatory role of PRMT1 on c-Fos
responses such as survival, apoptosis, differentiation and
proliferation by forming dimers. c-Fos is a subunit of AP-1 and METHODS
known as a proto-oncogene. The expression of c-Fos is tightly
regulated by numerous and complicated transcriptional and Luciferase assay was used to assess the transcriptional activity of
post-translational modifications (PTMs). Methylation is one of c-Fos in various experimental conditions. To confirm the autophagy
PTMs and regulates various signaling pathway including AP-1. and interaction between PRMT1 and c-Fos, confocal microscopy
Protein arginine methyltransferase 1 (PRMT1) catalyzed was employed. Immunoprecipitation and mass spectrometry were
transferring methyl group to arginine residue and generates conducted to identify the specific binding partners and methylation
mono-methyl arginine (mme-R) or asymmetric-di-methyl arginine sites. To determine degradation pathways, Cycloheximide (CHX)
(adme-R). chase assay and various degradation inhibitors were employed.
RESULTS
Our results demonstrated that the regulatory Figure 1. PRMT1 regulated AP-1 activity by modulating c-Fos
mechanism of c-Fos/AP-1 activity through
PRMT1. PRMT1 has specifically synergistic
effect on regulating c-Fos activity. The co-
localization of c-Fos and PRMT1 was in
cytosol, implying that PRMT1 as a non-histone
methyltransferase could directly regulated c-
Fos activity. c-Fos was di-methylated at
arginine by PRMT1, which was resulted in
increased c-Fos stability to regulate AP-1
activity. c-Fos stability was modulated by both Figure 2. PRMT1 methylated c-Fos to regulate stability
proteasomal and autophagic degradation but
PRMT1 solely involved in c-Fos autophagic
proteolysis. CHX chase assay showed that
PRMT 1 extended retention time of c-Fos.
Upon 3-MA treatment, c-Fos-mediated AP-1
activity was increasingly ascended.
Furthermore, c-Fos expression level was
diminished when PRMT1 is knockdown.
PRMT1-mediated c-Fos methylation at R287
modulated c-Fos stability resulting in
enhancement of c-Fos activity.
Figure 3. PRMT1 regulated c-Fos Figure 4. PRMT1 protected c-Fos Figure 5. Methylation of c-Fos is
stability from autophagy essential to protect degradation

CONCLUSION REFERENCES ACKNOWLEDGEMENTS
PRMT1-mediated c-Fos methylation at 1. Li, S.; Yang, P.; Tian, E.; Zhang, H., Arginine methylation This research was supported by the Basic
modulates autophagic degradation of PGL granules in C.
R287 regulated c-Fos stability resulting elegans. Molecular cell 2013, 52, (3), 421-433. Science Research Program through the
in enhancement of AP-1 activity 2. Kim, D.-I.; Park, M.-J.; Choi, J.-H.; Kim, I.-S.; Han, H.-J.; National Research Foundation (NRF) of
Yoon, K.-C.; Park, S.-W.; Lee, M.-Y.; Oh, K.-S.; Park, S.-H.,
PRMT1 and PRMT4 regulate oxidative stress-induced retinal Korea funded by the Ministry of Education
pigment epithelial cell damage in SIRT1-dependent and (2017R1A6A1A03015642)
SIRT1-independent manners. Oxidative medicine and cellular
longevity 2015, 2015. Contact information
3. Hess, J.; Angel, P.; Schorpp-Kistner, M., AP-1 subunits:
quarrel and harmony among siblings. Journal of cell science
2004, 117, (25), 5965-5973. Jae Youl Cho : jaecho@skku.edu
4. Mizushima, N., Autophagy: process and function. Genes &
development 2007, 21, (22), 2861-2873. Han Gyung Kim: hanks523@naver.com