The NH2 terminus of galectin-3 governs cellular compartmentalization and functions in cancer cells.

Galectin-3 is a member of the beta-galactoside-binding protein family shown to be involved in tumor progression and metastasis. It has a unique primary structure consisting of three domains: a 12-amino acid leader sequence containing a casein kinase I serine phosphorylation site, which is preceded by a collagenase-sensitive Pro-Gly-rich motif, and a COOH-terminal half encompassing the carbohydrate-binding site. To study the functional role of the unusual leader sequence of galectin-3, a mutant cDNA that causes an 11-amino acid deletion in the NH2-terminal region was generated and expressed in galectin-3-null BT-549 human breast carcinoma cells. Deletion of the NH2 terminus resulted in abolition of the secretion of truncated galectin-3, loss of nuclear localization, and reduced carbohydrate-mediated functions compared with the wild-type protein. When green fluorescent protein was fused to the galectin-3 leader sequence and transiently transfected into BT-549 cells, the uniform cellular distribution of native green fluorescent protein was changed mainly to a nuclear pattern. To further investigate whether the functional changes observed in a galectin-3 with the 11 NH2-terminal amino acids deleted were due to loss of phosphorylation at Ser6, two point mutations were created at this serine: Ser6-->Ala and Ser6-->Glu. No obvious difference was observed in cellular localization between wild-type and Ser6-mutated transfectants. These results suggest a structural role for the NH2 terminus leader motif of galectin-3 in determining its cellular targeting and biological functions independent of phosphorylation.

[Expression of thrombus regulatory protein and myeloperoxidasein peripheral blood of adult with obstructive sleep apnea hypopnea syndrome].

Objective:To investigate the expression of serum TM and MPO in adult patients with obstructive sleep apnea hypopnea syndrome(OSAHS).Method: Ninety OSAHS patients who confirmed by PSG as OSAHS group. According to AHI, the patients were divided into 3 groups include heavy, medium and light, and 30 healthy outpatients were control group. The serum TM and MPO were determined by ELISA; TM and MPO were measured after comprehensive treatment in patients with severe OSAHS, and the correlation between TM, MPO and PSG were analyzed. Result: ①With the severity of OSAHS patients increased, the serum levels of TM and MPO increased gradually（F=20.761,21.433；P<0.01). There was no significant difference about the concentration of TM and MPO between light and control group（P>0.05）；The concentration of TM and MPO was significantly higher in heavy and medium group compared with light and control group（P<0.01）.②There was no correlation between serum levels of TM, MPO, BMI, age and sex in OSAHS patients(P>0.05). The serum concentration of TM was positively related to MPO. The serum concentrations of TM and MPO were positively correlated with AHI, but negatively with LSaO2 (P<0.05). ③LSaO2 was significantly increased, AHI and peripheral blood TM, MPO levels were significantly reduced in thirty severe OSAHS cases received the combined treatment(P<0.01).Conclusion:The increase of TM and MPO concentration in peripheral blood is one of characteristics of cardiovascular damage in patients with OSAHS. Combined detection of serum TM and MPO concentrations in patients with the disease is helpful for evaluation and risk assessment of cardiovascular disease.

Tissue-specific expression and gabapentin-binding properties of calcium channel alpha2delta subunit subtypes.

We report here the tissue-specific expression and gabapentin-binding properties of calcium channel alpha2delta subunits. Northern blot analysis demonstrated that human alpha2delta-1, -2, and -3 mRNA all had high levels of expression in brain, heart and skeletal muscle. However, the highest expression of human alpha2delta-2 mRNA was found in lung. Human alpha2delta-1, -2, and -3 mRNAs were detected in all portions of brain tested. Western blotting revealed that alpha2delta-2 protein was predominantly expressed in cerebellar cortex (brain) and undetectable in lung. The dissociation between mRNA and protein levels of human alpha2delta-2 in lung suggests possible post-transcriptional regulation. Although mouse alpha2delta-1 proteins exhibited a similar tissue distribution profile as that of human, tissue distribution of mouse alpha2delta-2 and -3 mRNA revealed a different profile. Mouse alpha2delta-3 mRNA was restricted to brain and mouse alpha2delta-2 mRNA was not detectable in lung. Gel electrophoresis under a reduced condition resulted in a mobility shift of both alpha2delta-1 and alpha2delta-2 proteins, suggesting that alpha2 and delta of alpha2delta-2 protein are linked by disulfide bond as are alpha2 and delta of alpha2delta-1. Scatchard plots revealed a single population of gabapentin binding sites for human alpha2delta-2 with the KD value twofold higher than that of porcine alpha2delta-1 (156 +/- 25 nm vs. 72 +/- 9 nm). Inhibition of gabapentin binding to alpha2delta-2 by selected amino acids and gabapentin analogs produced a binding profile similar, but not identical to that of alpha2delta-1.