View source for Phosphatase Subfamily MTMR5

__NOTOC__

[[Phosphatase classification|Phosphatase Classification]]: [[Phosphatase_Fold_CC1|FoldCC1]]: [[Phosphatase_Superfamily_CC1|Superfamily CC1]]:  [[Phosphatase_Family_Myotubularin|Family Myotubularin]]: [[Phosphatase_Subfamily_MTMR1|Subfamily MTMR1]]

MTMR1 is a lipid phosphatase that dephosphorylates the second messenger phosphatidylinositol 3-monophosphate [PI(3)P].

===Evolution===
MTMR1 is found throughout [[holozoa]]. It consists of three members in human, MTM1, MTMR1 and MTMR2. In fruit fly and C elegans, a single copy is found. In most vertebrates from bony fish to human, MTM1 and MTMR1 are adjacent on the X chromosome (see [http://www.genomicus.biologie.ens.fr/genomicus-78.01/cgi-bin/phyloview.pl?root=2198950&amp;id=2199015&amp;xhide=108:107:105:110:69:96:97:63:111:-2198950:94:92:82:115:76:46:48:57:56:67:112:78:61:3:99:52:24:81:58:10:55:83&amp;xcollapse=-2198950&amp; Genomicus]).

===Domain Structure===
MTMR1 subfamily has a [http://pfam.xfam.org/family/PF02893.15 PH/GRAM] and phosphatase domain. The GRAM domain is similar to PH domain in structure and is found in membrane-associated proteins. As shown in [[Phosphatase_Subfamily_MTMR3|MTMR subfamily]], PH/GRAM domain can bind to phosphoinositide lipids. In Monosiga, the GRAM is replaced by a C1 domain, which is also a lipid-binding domain.

===Catalytic activity and functions===
Human MTM1 has phosphatase activity towards the second messenger phosphatidylinositol 3-monophosphate [PI(3)P] in vitro and in human, budding yeast, and fission yeast <cite>taylor00, blondeau00</cite>.
Human MTMR1 and MTMR2 have been shown to dephosphorylate PI(3)P (<cite>bujbello02</cite> and <cite>kim01</cite>, respectively). Although the enzymatic properties of the three human phosphatases are indistinguishable, their functions are not totally redundant. MTM1 and MTMR2 are differentially regulated in the aspects of developmental expression and subcellular localization, resulting in their use of specific cellular pools of PI(3)P <cite>kim01</cite>.

===Related Kinases===
See [http://en.wikipedia.org/wiki/Phosphoinositide_3-kinase PI3K].

===References===
<biblio>
#blondeau00 pmid=11001925
#taylor00 pmid=10900271
#bujbell02 pmid=12217958
#kim01 pmid=11733541
</biblio>