MHC class II gene regulation: some historical considerations on a still ontogenetic and phylogenetic puzzle

Accolla, Roberto S.; Tosi, Giovanna; Sartoris, Silvia; Barbaro, Andrea De Lerma

doi:10.1016/s1286-4579(99)00231-2

Cited by 4 publications

(2 citation statements)

References 55 publications

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“…an example where MARCH9 down-regulates an upstream target whose expression is required for HLA-DQ. HLA-DQ expression does require an unidentified additional cellular cofactor as interspecies somatic cell hybrids of the AIR-1 (class II transactivator)-defective human B cell line RJ 2.2.5 with mouse B cells rescues the surface expression of HLA-DR and -DP but not HLA-DQ despite normal expression of HLA-DQ transcripts (36, 37). Whether HLA-DQ or its predicted cofactor is the true target of MARCH9 needs to be determined.…”

Section: Discussionmentioning

confidence: 99%

Stable Isotope Labeling by Amino Acids in Cell Culture and Differential Plasma Membrane Proteome Quantitation Identify New Substrates for the MARCH9 Transmembrane E3 Ligase

Hör

Ziv

Admon

et al. 2009

Molecular & Cellular Proteomics

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The regulation of cell surface receptor expression is essential for immune cell differentiation and function. At the plasma membrane ubiquitination is an important post-translational mechanism for regulating expression of a wide range of surface proteins. MARCH9, a member of the RING-CH family of transmembrane E3 ubiquitin ligases, down-regulates CD4, major histocompatibility complex-I (MHC), and ICAM-1 in lymphoid cells. To identify novel MARCH9 substrates, we used high throughput flow cytometry and quantitative mass spectrometry by stable isotope labeling by amino acids in cell culture (SILAC) to determine the differential expression of plasma membrane proteins in a MARCH9-expressing B cell line. This combined approach identified 13 potential new MARCH9 targets. All of the SILAC-identified targets for which antibodies were available were subsequently confirmed by flow cytometry, validating the proteomics results. A close correlation (r2 = 0.93) between -fold down-regulation as determined by SILAC and flow cytometry was found, with no false positive hits detected. The potential new MARCH9 substrates cover a wide range of functions and include receptor-type protein-tyrosine phosphatases (e.g. PTPRJ/CD148) as well as Fc γ receptor IIB (CD32B), HLA-DQ, signaling lymphocytic activation molecule (CD150), and polio virus receptor (CD155). The identification of plasma membrane targets by SILAC with confirmation by flow cytometry represents a novel and powerful approach to analyze changes in the plasma membrane proteome.

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Section: Discussionmentioning

confidence: 99%

Stable Isotope Labeling by Amino Acids in Cell Culture and Differential Plasma Membrane Proteome Quantitation Identify New Substrates for the MARCH9 Transmembrane E3 Ligase

Hör

Ziv

Admon

et al. 2009

Molecular & Cellular Proteomics

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“…In vitro studies in both mouse and man have indicated that the transcription of HLA‐DQ locus products is controlled differently to that of HLA‐DR and ‐DP [18], particularly on epithelial cells. HLA‐DQ transcription was found to be largely independent of the class II transactivator (CIITA) [19].…”

Section: Discussionmentioning

confidence: 99%

Differential major histocompatibility complex class II locus expression on human laryngeal epithelium

Rees

Ayoub²,

Haverson

et al. 2003

Clinical and Experimental Immunology

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SUMMARYThe survival of a laryngeal allograft will be dependent on the immunological composition of the donor larynx and, in particular, on the expression of major histocompatibility complex (MHC) class II antigens on professional and non-professional antigen-presenting cells. Laryngeal and tonsillar biopsies from normal individuals aged 18-78 years were processed and prepared for quantitative, multiplecolour immunofluorescence using mouse antihuman monoclonal antibodies to human leucocyte antigen (HLA)-DR, HLA-DQ and CD45. The laryngeal epithelium expressed HLA-DR locus products at variable levels, but expression of HLA-DQ was virtually absent. Tonsillar epithelial cells expressed HLA-DR at the basal layer only, while HLA-DQ was similarly not expressed. In contrast, both HLA-DR and -DQ locus products were present on lamina propria and intraepithelial leucocytes in both laryngeal and tonsillar mucosae, although at varying levels. The finding that laryngeal epithelial cells express MHC class II antigens has implications for the survival of laryngeal allografts and suggests that they may require significant immunomodulation. In addition, antigen presentation by epithelial cells has been hypothesized to contribute to the immunoregulatory function of mucosal tissues, and the finding that HLA-DQ locus products are only expressed at low levels by laryngeal epithelium raises questions about the repertoire of peptides to which the mucosal immune system can respond.

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The AIR-1 encoded class II transactivator (CIITA): the master coordinator of MHC class II gene expression and ..more

Accolla

2001

Advances in Experimental Medicine and Biology

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MHC class II gene regulation: some historical considerations on a still ontogenetic and phylogenetic puzzle

Cited by 4 publications

References 55 publications

Stable Isotope Labeling by Amino Acids in Cell Culture and Differential Plasma Membrane Proteome Quantitation Identify New Substrates for the MARCH9 Transmembrane E3 Ligase

Stable Isotope Labeling by Amino Acids in Cell Culture and Differential Plasma Membrane Proteome Quantitation Identify New Substrates for the MARCH9 Transmembrane E3 Ligase

Differential major histocompatibility complex class II locus expression on human laryngeal epithelium

The AIR-1 encoded class II transactivator (CIITA): the master coordinator of MHC class II gene expression and ..more

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