Disease relevance of CD109

• Thus, these results suggested that CD109 might be a useful molecular target for the development of new therapeutics for malignant tumors, such as squamous cell carcinoma [1].
• When CD109 expression was examined in 33 cases of human lung cell carcinomas by quantitative RT-PCR, a significant high expression of CD109 was detected in about half of squamous cell carcinomas examined, but not in adenocarcinoma, large-cell carcinoma and small-cell carcinoma [1].
• BACKGROUND: Alloantibodies against the human platelet (PLT) alloantigen (HPA)-15 system residing on CD109 can cause fetal and neonatal alloimmune thrombocytopenia (FNAIT), posttransfusion purpura, and PLT transfusion refractoriness [2].
• Based on a phylogenic analysis of human CD109 with other human homologs as well as orthologs from other mammalian species, C. elegans (ZK337.1) and E. coli homologs, we propose CD109 represents a novel and independent branch of the alpha2-macroglobulin/complement gene family (AMCOM) and may be its oldest member [3].

High impact information on CD109

• Cell surface antigen CD109 is a glycosylphosphatidylinositol (GPI)-linked glycoprotein of approximately 170 kd found on a subset of hematopoietic stem and progenitor cells and on activated platelets and T cells [4].
• Cell surface antigen CD109 is a novel member of the alpha(2) macroglobulin/C3, C4, C5 family of thioester-containing proteins [4].
• We report that CD109 is a novel member of the alpha 2 macroglobulin (alpha 2M)/C3, C4, C5 family of thioester-containing proteins, and we demonstrate that native CD109 does indeed contain an intact thioester [4].
• As a first step toward elucidating the function of CD109, we have isolated and characterized a human CD109 cDNA from KG1a and endothelial cells [4].
• Similarly, upregulation of CD109 was observed in nine out of 17 esophageal squamous cell carcinomas [1].

Biological context of CD109

• The CD109 cDNA spans 128 kb of chromosome 6q with its 33 exons constituting approximately 3.3% of the total CD109 genomic sequence [3].
• The HPA-15 (Gov) alloantigen is a biallelic co-dominant system on human platelets, and its allele HPA-15a and HPA-15b differ by an A-->C single nucleotide polymorphism at nucleotide 2108 of the coding sequence resulting in a Tyr682Ser substitution in the mature CD109 glycoprotein [5].
• In the present study CD109 expression in cervical squamous cell carcinoma was compared with that in endometrial adenocarcinoma by reverse transcription polymerase chain reaction (RT-PCR) [6].

Anatomical context of CD109

• Northern blot analysis showed a high level of expression of the CD109 gene only in the testis in normal human and mouse tissues [1].
• We cloned full-length CD109 cDNA from the mammalian U373 cell line by RT-PCR and performed analysis of its corresponding genomic sequence [3].
• RESULTS: Expression of lymphocyte activation markers CD25, CDw108, and CD109 was equivalent when PBMCs incubated with group A and O RBCs were compared [7].
• The specificity of MoAb W7C5 was further confirmed by the selective recognition of CHO cells transfected with human CD109 cDNA [8].
• Antibody W7C5 defines a CD109 epitope expressed on CD34+ and CD34- hematopoietic and mesenchymal stem cell subsets [8].

Associations of CD109 with chemical compounds

• CD109 also shares motifs with certain other AMCOM members including: (1) a thioester 'GCGEQ" motif, (2) a furin site of four positively charged amino acids, and (3) a double tyrosine near the C-terminus [3].

Other interactions of CD109

• In addition, the predicted chemical reactivity of the activated CD109 thioester is complement-like rather than resembling that of alpha 2M proteins [4].
• Identification of CD109 as part of the TGF-beta receptor system in human keratinocytes [9].

Analytical, diagnostic and therapeutic context of CD109

• Sequence analysis revealed that CD109 contains specific motifs in its N-terminus, that are highly conserved in all AMCOM members [3].
• Based on the selection of PLTs expressing high amounts of CD109 on the surface (mean fluorescence intensity ratio 4-5 on expression peak on Days 2-4 after apheresis) antibody screening by the MAIPA assay was performed [2].
• Here, we show that CD109 expression was reduced upon platelet storage in saline or by cryopreservation, but was stable when stored as whole blood or therapeutic platelet concentrate [10].

References