[Surgical treatment of congenital muscular torticollis]. / Operative Behandlung des Torticollis muscularis congenitus.

OBJECTIVE: Surgical treatment of congenital muscular torticollis with tripolar release of the sternocleidomastoid muscle, followed by modified postoperative treatment with a special orthosis. INDICATIONS: Muscular torticollis due to contracture of the sternocleidomastoid muscle; failure of conservative therapy. CONTRAINDICATIONS: Torticollis due to bony anomaly or other muscular contractures. SURGICAL TECHNIQUE: Tenotomy of the sternocleidomastoid muscle occipitally and resection of at least 1 cm of the tendon at the sternal and clavicular origin. POSTOPERATIVE MANAGEMENT: Orthosis must be worn for 6 weeks 24 h/day, then for another 6 weeks 12 h/day. RESULTS: A total of 13 patients were treated with tripolar release of the sternocleidomastoid muscle and modified postoperative management. Average follow-up time was 25.7 months. One patient presented with recurrence after 3 years. No intra- or postoperative complications were observed.

A cysteine protease-like domain enhances the cytotoxic effects of the Photorhabdus asymbiotica toxin PaTox.

The nematode mutualistic bacterium Photorhabdus asymbiotica produces a large virulence-associated multifunctional protein toxin named PaTox. A glycosyltransferase domain and a deamidase domain of this large toxin function as effectors that specifically target host Rho GTPases and heterotrimeric G proteins, respectively. Modification of these intracellular regulators results in toxicity toward insects and mammalian cells. In this study, we identified a cysteine protease-like domain spanning PaTox residues 1844-2114 (PaToxP), upstream of these two effector domains and characterized by three conserved amino acid residues (Cys-1865, His-1955, and Asp-1975). We determined the crystal structure of the PaToxP C1865A variant by native single-wavelength anomalous diffraction of sulfur atoms (sulfur-SAD). At 2.0 Å resolution, this structure revealed a catalytic site typical for papain-like cysteine proteases, comprising a catalytic triad, oxyanion hole, and typical secondary structural elements. The PaToxP structure had highest similarity to that of the AvrPphB protease from Pseudomonas syringae classified as a C58-protease. Furthermore, we observed that PaToxP shares structural homology also with non-C58-cysteine proteases, deubiquitinases, and deamidases. Upon delivery into insect larvae, PaToxP alone without full-length PaTox had no toxic effects. Yet, PaToxP expression in mammalian cells was toxic and enhanced the apoptotic phenotype induced by PaTox in HeLa cells. We propose that PaToxP is a C58-like cysteine protease module that is essential for full PaTox activity.

Tyrosine glycosylation of Rho by Yersinia toxin impairs blastomere cell behaviour in zebrafish embryos.

Yersinia species cause zoonotic infections, including enterocolitis and plague. Here we studied Yersinia ruckeri antifeeding prophage 18 (Afp18), the toxin component of the phage tail-derived protein translocation system Afp, which causes enteric redmouth disease in salmonid fish species. Here we show that microinjection of the glycosyltransferase domain Afp18(G) into zebrafish embryos blocks cytokinesis, actin-dependent motility and cell blebbing, eventually abrogating gastrulation. In zebrafish ZF4 cells, Afp18(G) depolymerizes actin stress fibres by mono-O-GlcNAcylation of RhoA at tyrosine-34; thereby Afp18(G) inhibits RhoA activation by guanine nucleotide exchange factors, and blocks RhoA, but not Rac and Cdc42 downstream signalling. The crystal structure of tyrosine-GlcNAcylated RhoA reveals an open conformation of the effector loop distinct from recently described structures of GDP- or GTP-bound RhoA. Unravelling of the molecular mechanism of the toxin component Afp18 as glycosyltransferase opens new perspectives in studies of phage tail-derived protein translocation systems, which are preserved from archaea to human pathogenic prokaryotes.

Intracellular plasma membrane guidance of Photorhabdus asymbiotica toxin is crucial for cell toxicity.

The bacterial toxin Photorhabdus asymbiotica toxin (PaTox) modifies Rho proteins by tyrosine GlcNAcylation and heterotrimeric Gα proteins by deamidation. Inactivation of Rho proteins results in F-actin disassembly in host cells. Here, we analyzed the subcellular distribution of PaTox and show that the glycosyltransferase domain of PaTox associates with the negatively charged inner surface of the plasma membrane. Localization studies with site-directed mutants, liposome precipitation analysis, lipid overlay assays, and confocal time-lapse microscopy revealed that a patch of positively charged lysine and arginine residues located on helix α1 of the glycosyltransferase is essential for membrane attachment. Using a helix1 deletion mutant, we show that plasma membrane localization of PaTox is essential for cytotoxicity and proved this by substitution of helix1 by an N-terminal myristoylation signal peptide, which restored plasma membrane localization and cytotoxicity. Furthermore, we also show that the intracellular deamidase activity of PaTox depends on the presence of the membrane localization domain. Comparison of PaTox membrane-binding domain with the 4-helix-bundle membrane-binding domain of Pasteurella multocida toxin, Vibrio cholerae multifunctional autoprocessing repeats-in-toxin, and clostridial glucosylating toxins revealed similar spatial geometry and charge distribution but different structural topology, indicating convergent evolution of toxin domains for optimized host target interaction.