Phosphatase Subfamily Dullard

Phosphatase Classification: FCP: Subfamily Dullard

Dullard, is also known as CTDNEP1 (CTD nuclear envelope phosphatase 1). It participates in a unique phosphatase cascade regulating nuclear membrane biogenesis, and the cascade is conserved from yeast to human [1] (in particular, Figure 5B). Dullard, as well as its substrate, phosphatidic acid phosphatase, lipin, is conserved from yeast to human.

Evolution

Dullard is conserved from yeast to human, so is its substrate lipin and the kinases phosphorylating lipin. However, interestingly, the described kinases in yeast and mammals are of different families, though both of them are present in yeast and mammals.

Substrates and Related Kinases

	Phosphatase	Lipin	Kinase
Yeast	Nem1-Spo7 complex	Smp2	Cdc28/Cdk1
Mammals	Dullard (-? complex)	LIPIN	mTOR

Notes:

1. Cdc28/Cdk1 (in yeast). Smp2 is phosphorylated by Cdc28/Cdk1 and dephosphorylated by a nuclear/endoplasmic reticulum (ER) membrane-localized CPD phosphatase complex consisting of Nem1 and Spo7 [2].

2. mTOR (in mammals). Lipin has multiple phosphorylation sites. Though many kinases may involve in the multisite phosphorylation, mTOR plays an important role [3].

References

1. Kim Y, Gentry MS, Harris TE, Wiley SE, Lawrence JC Jr, and Dixon JE. A conserved phosphatase cascade that regulates nuclear membrane biogenesis. Proc Natl Acad Sci U S A. 2007 Apr 17;104(16):6596-601. DOI:10.1073/pnas.0702099104 |
2. Santos-Rosa H, Leung J, Grimsey N, Peak-Chew S, and Siniossoglou S. The yeast lipin Smp2 couples phospholipid biosynthesis to nuclear membrane growth. EMBO J. 2005 Jun 1;24(11):1931-41. DOI:10.1038/sj.emboj.7600672 |
3. Huffman TA, Mothe-Satney I, and Lawrence JC Jr. Insulin-stimulated phosphorylation of lipin mediated by the mammalian target of rapamycin. Proc Natl Acad Sci U S A. 2002 Jan 22;99(2):1047-52. DOI:10.1073/pnas.022634399 |

Links

Human Dullard from NCBI Gene