| First Author | Cordell PA | Year | 2015 |
| Journal | Matrix Biol | Volume | 43 |
| Pages | 85-96 | PubMed ID | 25680676 |
| Mgi Jnum | J:224424 | Mgi Id | MGI:5662191 |
| Doi | 10.1016/j.matbio.2015.02.001 | Citation | Cordell PA, et al. (2015) Normal Bone Deposition Occurs in Mice Deficient in Factor XIII-A and Transglutaminase 2. Matrix Biol 43:85-96 |
| abstractText | Transglutaminase activity has been widely implicated in bone deposition. A predominant role has been proposed for factor (F)XIII-A and a subsidiary role suggested for the homologous protein, transglutaminase 2. Full-length FXIII-A is an 83kDa protransglutaminase that is present both in plasma and also in haematopoietic and connective tissue lineages. Several studies have reported expression in murine cells, including osteocytes, of a 37 kDa protein that reacts with the monoclonal anti-FXIII-A antibody AC-1A1. This protein was presumed to be a catalytically active fragment of FXIII-A-83 and to play a major role in bone deposition. We detected a 37 kDa AC-1A1 reactive protein in FXIII-A mRNA negative cell lines and in tissues from FXIII-A(-/-) mice. By mass spectrometric sequencing of AC-1A1 immunoprecipitates, we identified this protein as transaldolase-1, and confirmed that recombinant transaldolase-1 is recognised by AC-1A1. We have also shown that bone deposition is normal in FXIII-A(-/-).TG2(-/-) double knockout mice, casting doubt on the role of transglutaminases in bone mineralisation. Various studies have used antibody AC-1A1 for immunohistochemistry or immunofluorescence. We observe strong FXIII-A dependent staining in paraffin embedded mouse heart sections, with relatively low background in non-expressing mouse cells. In contrast, FXIII-A independent staining predominates in cultured human cells using a standard immunofluorescence procedure. Immunofluorescence is present in membrane compartments that are expected to lack transaldolase, indicating that other off-target antigens are recognised by AC-1A1. This has significant implications for studies that have used this approach to define the subcellular trafficking of FXIII-A in osteocytes. |
