Home | Contact

Myotubularin phosphatases are members of the protein tyrosine phosphatase (PTP) superfamily. The PTP domain is found in a diverse group of enzymes that catalyze phosphoester hydrolysis using a cysteine nucleophile and an arginine residue that binds to oxygen atoms of the phosphate. These two catalytically essential residues are found in a Cys-x(5)-Arg motif, which is a hallmark of PTP domains (see <PDOC00323>). The PTP superfamily of enzymes includes tyrosine-specific, dual specificity, low molecular weight, and Cdc25 phosphatases. All of these enzymes utilize phosphoproteins as substrates. Unlike these members of PTPs, enzymes that contain the tensin (see <PDOC51181>) and myotubularin PTP domain utilize the phosphoinositide as its physiologic substrate. Myotubularins are 3-phosphatases specific for membrane-embedded PtdIns3P and PtdIns(3,5)P2, two PIs that function within the endosomal-lysosomal pathway [1,2].

The myotubularin phosphatase domain consists of a central seven stranded β sheet flanked by thirteen α helices (see <PDB:1LW3>) [3]. Although its core structure is similar to that of other PTP superfamily members, the myotubularin phosphatase domain is much larger. It contains an extra C-terminal region, which could be implicated in protein-protein interactions. The active site motif forms a P-loop at the base of a substrate binding pocket that is characteristic of PTP domains. This pocket is significantly deeper than that of other PTP pockets, which could explain the difference in substrate specificity.

The profile we developed covers the whole myotubularin phosphatase domain.

November 2007 / First entry.

PROSITE method (with tools and information) covered by this documentation:

PPASE_MYOTUBULARIN, PS51339; Myotubularin phosphatase domain  (MATRIX)

Sequences known to belong to this class detected by the profile: ALL Other sequence(s) detected in Swiss-Prot: NONE

• Domain architecture view of Swiss-Prot proteins matching PS51339 • Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS51339 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS51339 • Scan Swiss-Prot/TrEMBL entries against PS51339 • view ligand binding statistics

Matching PDB structures: 1LW3 1M7R 1ZSQ 1ZVR ... [ALL]

1	Authors	Denu J.M., Dixon J.E.
	Title	Protein tyrosine phosphatases: mechanisms of catalysis and regulation.
	Source	Curr. Opin. Chem. Biol. 2:633-641(1998).
	PubMed ID	9818190

2	Authors	Robinson F.L., Dixon J.E.
	Title	Myotubularin phosphatases: policing 3-phosphoinositides.
	Source	Trends Cell Biol. 16:403-412(2006).
	PubMed ID	16828287
	DOI	10.1016/j.tcb.2006.06.001

3	Authors	Begley M.J., Taylor G.S., Kim S.A., Veine D.M., Dixon J.E., Stuckey J.A.
	Title	Crystal structure of a phosphoinositide phosphatase, MTMR2: insights into myotubular myopathy and Charcot-Marie-Tooth syndrome.
	Source	Mol. Cell 12:1391-1402(2003).
	PubMed ID	14690594

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to

Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)

SIB Swiss Institute of Bioinformatics | Disclaimer