Phakomatosis Pigmentovascularis Associated With Sturge-Weber Syndrome, Ota Nevus, and Congenital Glaucoma.

Phakomatosis pigmentovascularis (PPV) is a rare congenital malformation syndrome that is characterized by a combination of capillary abnormalities and dermal melanocytosis.We describe 3 cases of PPV combined with bilateral Sturge-Weber syndrome (SWS), Ota nevus, and congenital glaucoma.Case 1 was a 2-year-old boy. Facial port-wine stains distributed along the 3 branches of his trigeminal nerves, which suggested the existence of SWS. Gray-blue patches were spread over the frontal and temporal areas of bilateral face, waist, buttocks, and thigh. Bilateral triangular alopecia was found on the temporal scalp. The diagnosis of Ota nevus was made by the bilateral scleral malanocystosis. Increased intraocular pressure, enlarged cornea, and pathologic optic disc cupping supported the diagnoses of infantile bilateral glaucoma. Case 2 was a 4-year-old boy. Port-wine stains were found on the face along the 3 branches of the trigeminal nerve and distributed along the trunk, arms, and legs. Mongolian spots spread over his frontal and temporal areas of the bilateral face, waist, buttocks, thigh, abdomen, and back. Infantile glaucoma was found in both eyes. Ota nevus were found in the both eyes. Optic coherent tomography (OCT) scans revealed increased thickness of choroid. Case 3 was a 5-year-old boy. Besides Ota nevus and infantile glaucoma in both eyes, color Doppler ultrasonography showed choroidal hemagioma. OCT scan showed increased choroidal thickness. The bilateral triangular alopecia on the child's temporal scalp was similar to that of Case 1. Cases 1 and 2 presented with port-wine stain patches that were consistent with the characteristic manifestation of PPV type IIb. However, the CMTC of Case 3 met the diagnostic criteria for PPV type Vb.Case 1 was treated with trabeculotomies in both eyes. For Cases 2 and 3, surgical interventions were not considered due to the high risks of antiglaucomatous operation complications. We prescribed them antiglaucoma indications.The simultaneously coexistence of PPV with SWS, Ota nevus, and congenital glaucoma is rare. In the clinic, additional detailed examinations and tests of PPV patients to exclude other ocular abnormalities or extraocular involvements are necessary.

Fluorescence complementation via EF-hand interactions.

Fluorescence complementation technology with fluorescent proteins is a powerful approach to investigate molecular recognition by monitoring fluorescence enhancement when non-fluorescent fragments of fluorescent proteins are fused with target proteins, resulting in a new fluorescent complex. Extension of the technology to calcium-dependent protein-protein interactions has, however, rarely been reported. Here, a linker containing trypsin cleavage sites was grafted onto enhanced green fluorescent protein (EGFP). Under physiological conditions, a modified fluorescent protein, EGFP-T1, was cleaved into two major fragments which continue to interact with each other, exhibiting strong optical and fluorescence signals. The larger fragment, comprised of amino acids 1-172, including the chromophore, retains only weak fluorescence. Strong green fluorescence was observed when plasmid DNA encoding complementary EGFP fragments fused to the EF-hand motifs of calbindin D9k (EF1 and EF2) were co-transfected into HeLa cells, suggesting that chromophore maturation and fluorescence complementation from EGFP fragments can be accomplished intracellularly by reassembly of EF-hand motifs, which have a strong tendency for dimerization. Moreover, an intracellular calcium increase upon addition of a calcium ionophore, ionomycin in living cells, results in an increase of fluorescence signal. This novel application of calcium-dependent fluorescence complementation has the potential to monitor protein-protein interactions triggered by calcium signalling pathways in living cells.

Identification of a Ca2+-binding domain in the rubella virus nonstructural protease.

The rubella virus (RUB) nonstructural protein (NS) open reading frame (ORF) encodes a polypeptide precursor that is proteolytically self cleaved into two replicase components involved in viral RNA replication. A putative EF-hand Ca(2+)-binding motif that was conserved across different genotypes of RUB was predicted within the nonstructural protease that cleaves the precursor by using bioinformatics tools. To probe the metal-binding properties of this motif, we used an established grafting approach and engineered the 12-residue Ca(2+)-coordinating loop into a non-Ca(2+)-binding scaffold protein, CD2. The grafted EF-loop bound to Ca(2+) and its trivalent analogs Tb(3+) and La(3+) with K(d)s of 214, 47, and 14 microM, respectively. Mutations (D1210A and D1217A) of two of the potential Ca(2+)-coordinating ligands in the EF-loop led to the elimination of Tb(3+) binding. Inductive coupled plasma mass spectrometry was used to confirm the presence of Ca(2+) ([Ca(2+)]/[protein] = 0.7 +/- 0.2) in an NS protease minimal metal-binding domain, RUBCa, that spans the EF-hand motif. Conformational studies on RUBCa revealed that Ca(2+) binding induced local conformational changes and increased thermal stability (Delta T(m) = 4.1 degrees C). The infectivity of an RUB infectious cDNA clone containing the mutations D1210A/D1217A was decreased by approximately 20-fold in comparison to the wild-type (wt) clone, and these mutations rapidly reverted to the wt sequence. The NS protease containing these mutations was less efficient at precursor cleavage than the wt NS protease at 35 degrees C, and the mutant NS protease was temperature sensitive at 39 degrees C, confirming that the Ca(2+)-binding loop played a structural role in the NS protease and was specifically required for optimal stability under physiological conditions.