1. Methyltransferase Set7/9 regulates p53 activity by interacting with Srituin 1 (SIRT1)

2. SIRT1 (Sirtuin 1)
A mamalian NAD+-dependent hitone deacetylase (HDAC)
It deacetylates tumor suppressor such as p53 and FoxO
HIC (hypermethylated in cancer 1) inhibit SIRT1
DBC (deleted in breast cancer 1) is negative repressor of SIRT1
AROS (active regulator of SIRT1)
Set7/9
Monomethyltransferase for histone H3K4 methylation

3. Results
Set7/9 regulates p53 activity through a p53 K372 methylation independent mechanism

4. SIRT1 interacts with Set7/9

5. SIRT1 is methylated at multiple lysines

6. Methylation of SIRT1 is dispensable for its deacetylase activity

7. Interaction between set7/9 and SIRT1 induces the dissociation of SIRT1 from p53 and, in turn, increase p53 activity

8. Discussion
Posttranslational modification of SIRT1 influence SIRT1 activity
Sumoylation at lysine 278
Physphorylation of SIRT1 serine residues
Set7/9 methylation is not always related to functional changes of targeted molecules
Methylation of SIRT1 by Set7/9 did not affect deacety lase activity
Interaction between SIRT1 and Set7/9 was required for the dissociation of SIRT1 from p53.