Complement in membranoproliferative (hypocomplementaemic) glomerulonephritis.

Factor H-related protein-5 (FHR-5) is a newly described human plasma protein with structural similarities to human factor H and the four other recently described factor H-related proteins. Unlike the other factor H-related proteins, FHR-5 was initially identified at the protein, rather than complementary DNA, level in studies of glomerular immune deposit composition. To determine the incidence and pattern of detection of FHR-5 in human renal biopsy specimens, a prospective study of 100 consecutive biopsies was performed using anti-FHR-5 monoclonal antibody and indirect immunofluorescence. The pattern of FHR-5 deposition is very similar to that of other complement components, C3 and SC5b-9. It is detected in all complement-containing glomerular immune deposits and has a pattern of extraglomerular deposition similar to that of other complement components. This study shows FHR-5 to be strongly associated with glomerular complement deposition and suggests a role in complement activation or regulation. It may be an important mediator of glomerular disease.

Blood Proteins↗

PubMed2002

Identification of specific proteins in different lymphocyte populations by proteomic tools.

The solubilized proteins of purified CD19(+) (B), CD8(+) (T) as well as CD4(+) (T) lymphocytes were separated by high resolution two-dimensional polyacrylamide gel electrophoresis, and the gels were analyzed using Melanie 3.0. Nine gels were studied, three for each lymphocyte population. After image analysis, 1411 +/- 73 spots (mean + SD) were detected. The protein pattern of B lymphocytes segregated from the one of T lymphocytes by ascendant heuristic clustering analysis. In addition, computer analysis separated CD8(+) from CD4(+) lymphocytes. When a search was performed in order to detect subsets of specific spots (presence vs. absence), a group of three spots, detected in the area of the protein maps corresponding to isoelectric point (pI) of 5.2 to 5.4 and molecular weight (M(r)) of 50 to 51 kDa, were found in both CD8(+) and CD4(+) cells, but not in CD19(+) cells. Mass spectrometry analysis revealed that these spots were associated with several proteins such as vimentin, tubulin, desmin and cytokeratin. Two spots, located in the area of the gel corresponding to pI of about 5.0 and a M(r) of 30 kDa, appeared as CD8(+) cell associated. Mass spectrometry analysis showed that the two spots were related to the same non-identified protein. Moreover internal peptides sequences matched with two human expressed sequence tags: gi/9759776, gi/12798420. No spots were found as only B cell associated.

Blood Proteins↗

PubMed2001

RB2/p130 ectopic gene expression in neuroblastoma stem cells: evidence of cell-fate restriction and induction of differentiation.

The activity of the RB2/p130 gene, which is a member of the retinoblastoma gene family, is cell-cycle-regulated and plays a key role in growth inhibition and differentiation. We used neuroblastoma cell lines as a model for studies on neural crest progenitor cell differentiation. We show that Rb2/p130 ectopic protein expression induces morphological and molecular modifications, promoting differentiation of intermediate (I) phenotype SK-N-BE(2)-C neuroblastoma cells towards a neuroblastic (N) rather than a Schwann/glial/melanocytic (S) phenotype. These modifications are stable as they persist even after treatment with an S-phenotype inducer. Rb2/p130 ectopic expression also induces a more differentiated phenotype in N-type SH-SY-5Y cells. Further, this function appears to be independent of cell-cycle withdrawal. The data reported suggest that the Rb2/p130 protein is able to induce neuronal lineage specification and differentiation in neural crest stem and committed neuroblastoma cells, respectively. Thus, the Rb2/p130 protein seems to be required throughout the full neural maturation process.

Blood Proteins↗