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  • The EMBO Journal (2002) 21, 5467 - 5476
  • doi:10.1093/emboj/cdf557

Phosphorylation of CIITA directs its oligomerization, accumulation and increased activity on MHCII promoters

Giovanna Tosi2, Nabila Jabrane-Ferrat1 and B.Matija Peterlin1

  1. Departments of Medicine, Microbiology and Immunology, Rosalind Russell Medical Research Center, University of California, San Francisco, CA 94115-0703, USA
  2. Present address: Department of Clinical and Biological Sciences, School of Medicine, University of Insubria, Viale L.Borri 57, Varese, Italy

Correspondence to:

B.Matija Peterlin, E-mail: matija@itsa.ucsf.edu

Received 25 March 2002; Accepted 30 August 2002; Revised 29 August 2002

The class II transactivator (CIITA) is the master regulator of major histocompatibility complex class II (MHCII) transcription. Its activity is regulated at the post-transcriptional level by phosphorylation and oligomerization. This aggregation mapped to and depended on the phosphorylation of residues between positions 253 and 321 in CIITA, which resulted in a dramatic accumulation of the protein and increased expression of MHCII genes in human promonocytic U937 cells, which represent immature antigen-presenting cells. Thus, the post-transcriptional modification of CIITA plays an important role in the immune response.

  • Keywords:

    • CIITA,
    • MHCII transcription,
    • oligomerization,
    • phosphorylation