Figure 1 Myotubularin exhibits a tyrosine phosphatase activity Figure 1 Myotubularin exhibits a tyrosine phosphatase activity. Bars show the activity of either wild-type or mutated myotubularin in the presence or absence of several inhibitors. p-NPP was used as substrate. Values are percentages of the activity of wild-type myotubularin at 6 ng/µl and represent the means ± SD of two independent experiments (each performed in duplicate). CON, control, i.e. wild-type baculovirus; WT, wild-type myotubularin; C→S, mutated myotubularin; 1, 0.1 mM sodium orthovanadate; 2, 1 mM sodium orthovanadate; 3, 10 mM sodium orthovanadate; 4, 5 µM okadaic acid; 5, 10 mM sodium phosphate. From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press

Figure 2 Representation of the partial or complete coding sequences of members of the MTM family. The horizontal lines represent the span of the sequenced coding region of each gene. We have designated the human genes MTMR1-MTMR7 (R for related) and used the same R designation for the corresponding mouse and zebrafish orthologues. When the correspondence with a human gene cannot be unambiguously determined, we have designated the genes MTMH (H for homologue). M is the methionine start codon, and stars represent stop codons. The first methionine (M) is not conserved between hMTMR1 and mMTMR1 . The hMTMR1 cDNA clone appears chimeric, as several cDNA clones cover the N-terminal part of mMTMR1 , and this is confirmed by 209 kb of genomic sequence (AA002223) available for hMTMR1 . A black filled square denotes a PTP/DSP signature, and an empty square stands for a variant signature. The comparison area used in Figure 3 is shown by a double arrowed line. The GenBank accession nos related to the different genes are as follow: hMTM1 , U46024; hMTMR1 , U58032; hMTMR2 , U58033; hMTMR3 , U58034; hMTMR4 , EST AA317931; hMTMR5 , AF072929; hMTMR6 , AF072928; hMTMR7 , AF073482; mMTM1 , AF073996; mMTMR1 , AF073997; mMTMR7 , AF073882; mMTMH1 , AF073879; mMTMH2 , AF073880; mMTMH3 , AF073881; zMTMR2 , AF073883; dMTMH1 , AF076432, and AC002594 for cosmid DS05973; ceMTH1 , AF031519, in cosmid T24A11; ceMTH2 , Z81546 and ORF F53A2.8, in cosmid F53A2; scMTMH , Z49610; spMTMH , Z98974. One additional gene is present in Drosophila , defined by recently deposited sequences (see Materials and Methods). EST contigs found in the TIGR database ( http://www.tigr.org ): hMTM1 , THC2108331, HT48648; hMTMR1 , THC211120, HT48723; hMTMR2 , THC211460, HT48724; hMTMR3 , THC214662, HT48725; hMTMR5 , THC207058. From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press

Figure 3 Conservation of the MTM family around the PTP/DSP active site Figure 3 Conservation of the MTM family around the PTP/DSP active site. Alignment of deduced amino acid sequences from ESTs and cDNAs from the MTM family: protein sequence comparison around the PTP/DSP active site (202 amino acids between positions 337 and 538 in hMTM1). hMTMR4, mMTMH2 and mMTMH3 were not compared as their sequences do not encompass the full comparison area. A 70 and a 38 amino acid segment were excluded in the scMTMH and spMTMH sequences respectively (indicated by XX), as they have no counterpart in the other members of the MTM family. Boxed residues are conserved in the majority of the members. The PTP/DSP active site is underlined, as is the SID domain defined by Cui et al . ( 10 ) (dashed line). From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press

Figure 4 Evolutionary relationship of members of the MTM family Figure 4 Evolutionary relationship of members of the MTM family. The unrooted phylogenetic tree was generated from the amino acid alignment in Figure 3 using random number generator seed 500 and number of bootstrap trials 5000 as parameters. The bootstrap value is indicated at each branching and the scale indicates the phylogenetic distance. From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press

Figure 5 Sequence alignement of hMTM1 and dMTMH1 and position of missense mutations. The upper sequence is human myotubularin (hMTM1) and the lower one the homologue in Drosophila (dMTMH1), 603 and 619 amino acids long, respectively. They display a similarity of 70% and an identity of 55%. The PTP/DSP consensus and the SID are underlined (plain and dashed lines, respectively). The missense mutations found in XLMTM patients have been previously reported ( 4 , 5 ) and are shown above the human myotubularin sequence. Δ deletion of an amino acid; +, insertion of three amino acids (FIQ) following a serine residue. The upper line over the two Ns indicates a double missense found in the same patients. The asterisks indicate the two conserved Asp residues flanking the active site. From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press

Table 1 Tissue expression and chromosomal localization of the human MTMR genes From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press

Figure 6 Tissue expression of the human MTM genes Figure 6 Tissue expression of the human MTM genes. Northern blot analysis in different tissues indicated at the top. Transcripts sizes were determined from the size marker range. Results for hMTM1 and hMTMR1 have been previously reported ( 3 ) and are shown here for comparison. The expression of hMTMR7 is brain specific but present in all compartments of the brain tested. From: Characterization of the Myotubularin Dual Specificity Phosphatase Gene Family from Yeast to Human Hum Mol Genet. 1998;7(11):1703-1712. doi:10.1093/hmg/7.11.1703 Hum Mol Genet | © 1998 Oxford University Press