Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD79a and CD79b function as transducers of B cell antigen receptor signals via a cytoplasmic sequence, termed the immunoreceptor tyrosine-based activation motif (ITAM). ITAMs contain two conserved tyrosines that may become phosphorylated upon receptor aggregation and bind distinct effectors by virtue of the distinct preference of phosphotyrosyl-containing sequences for SH2 domains. To explore the function of CD79a and CD79b ITAM tyrosines, we created membrane molecules composed of MHC class II I-Ak extracellular and transmembrane domains, and CD79a or CD79b cytoplasmic domains in which one or both of the ITAM tyrosines were mutated to phenylalanine. Functional analysis revealed that both ITAM tyrosines are required for ligand-induced Syk phosphorylation. However CD79a-ITAM and CD79b-ITAM tyrosine phosphorylations were asymmetrical, with >80% of phosphorylation occurring on the N-terminal tyrosine (Y-E-G-L). Thus, these findings suggest that following receptor ligation, only a minor proportion of phosphorylated ITAMs are doubly phosphorylated and thus can engage Syk. Only the N-terminal ITAM tyrosine of CD79a was required for ligand-mediated phosphorylation of the receptor and a subset of downstream substrates, including p62, p110, and Shc, and for Ca2+ mobilization. However, responses mediated through CD79b exhibited a greater dependence on the presence of both tyrosines. Neither tyrosine in CD79a or CD79b appeared absolutely essential for Src family kinase phosphorylation. These results indicate that phosphorylations of the tyrosines in CD79a and CD79b occur with very different stoichiometry, and the respective tyrosyl residues have distinct functions.
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PMID:Asymmetrical phosphorylation and function of immunoreceptor tyrosine-based activation motif tyrosines in B cell antigen receptor signal transduction. 953 Dec 88

An acute to chronic idiopathic necrotizing meningoencephalitis was diagnosed in 5 Chihuahua dogs aged between 1.5 and 10 years. Presenting neurologic signs included seizures, blindness, mentation changes, and postural deficits occurring from 5 days to 5.5 months prior to presentation. Cerebrospinal fluid analyses from 2 of 3 dogs sampled were consistent with an inflammatory disease. Magnetic resonance imaging of the brain of 2 dogs demonstrated multifocal loss or collapse of cortical gray/white matter demarcation hypointense on T1-weighted images, with T2-weighted hyperintensity and slight postcontrast enhancement. Multifocal asymmetrical areas of necrosis or collapse in both gray and white matter of the cerebral hemispheres was seen grossly in 4 brains. Microscopically in all dogs, there was a severe, asymmetrical, intensely cellular, nonsuppurative meningoencephalitis usually with cystic necrosis in subcortical white matter. There were no lesions in the mesencephalon or metencephalon except in 1 dog. Immunophenotyping defined populations of CD3, CD11d, CD18, CD20, CD45, CD45 RA, and CD79a immunoreactive inflammatory cells varying in density and location but common to acute and chronic lesions. In fresh frozen lesions, both CD1b,c and CD11c immunoreactive dendritic antigen-presenting cells were also identified. Immunoreactivity for canine distemper viral (CDV) antigen was negative in all dogs. The clinical signs, distribution pattern, and histologic type of lesions bear close similarities to necrotizing meningoencephalitis as described in series of both Pug and Maltese breed dogs and less commonly in other breeds.
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PMID:Necrotizing meningoencephalitis in five Chihuahua dogs. 1848 90

Eosinophilic meningoencephalitis (EME) has been described in various species of animals and in humans. In dogs it has been associated with protozoal infections, cuterebral myiasis and various other aetiologies. Ten cases of idiopathic eosinophilic meningoencephalitis have been reported in dogs and one in a cat where the origin was uncertain or unknown. The dogs were all males, of various breeds but with a predominance of Golden Retrievers and Rottweilers; they generally had a young age of onset. Two cases with no apparent underlying aetiology were diagnosed on post mortem examination. The 18-month-old, male Boerboel presented with sudden onset of cerebellar ataxia, as well as various asymmetrical cranial nerve deficits of 2 weeks' duration and without progression. Haematology revealed a peripheral eosinophilia. Necropsy showed extreme generalised congestion especially of the meninges and blood smear and histological sections of various tissues showed intravascular erythrocyte fragmentation with the formation of microcytes. Histopathology revealed severe diffuse cerebrocortical subarachnoidal meningitis and submeningeal encephalitis, the exudate containing variable numbers of eosinophils together with neutrophils and mononuclear cells. There was also deeper white matter and hippocampal multifocal perivascular mononuclear encephalitis and multifocal periventricular malacia, gliosis and phagocytosis of white matter. The cerebellum, brain stem and spinal c showed only mild multifocal oedema or scattered occasional axon and myelin degeneration respectively, with no inflammation. Immunohistochemical staining of central nervous tissue for Toxoplasma gondii failed to show any antigen in the central nervous tissue. Ultrastructure of a single submeningeal suspected parasitic cyst showed it to be chromatin clumping within a neuron nucleus indicating karyorrhexis. Gram stain provided no evidence of an aetiological agent. The 3-year-old Beagle bitch had a Caesarian section after developing a non-responsive inertia 8 days prior to presentation. This animal's clinical signs included status epilepticus seizures unrelated to hypocalcaemia and warranted induction of a barbiturate coma. She died 4 hours later. Post mortem and histopathological findings in the brain were almost identical to those of the Boerboel and she also showed histological evidence of recent active intravascular haemolysis with microcyte formation. Rabies, distemper and Neospora caninum immunohistochemical stains were negative in the brains of both dogs. Immunohistochemical staining of the cerebral and meningeal exudates of the Beagle for T- and B-lymphocyte (CD3 and CD79a) markers showed a predominance of T-lymphocytes with fewer scattered B lymphocytes. A possible allergic response to amoxicillin/clavulanate is considered, as this appeared to be the only feature common to the recent history of both animals. An overview of EME in humans, dogs and cats is given and the previously published cases of idiopathic EME in dogs and the single published cat case are briefly reviewed.
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PMID:Review of idiopathic eosinophilic meningitis in dogs and cats, with a detailed description of two recent cases in dogs. 1949 20