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A novel member of the TRAF family of putative signal transducing proteins binds to the cytosolic domain of CD40
Author(s) -
Sato Takaaki,
Irie Shinji,
Reed John C.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01406-q
Subject(s) - zinc finger , cytosol , biology , microbiology and biotechnology , ring finger domain , c2 domain , signal transduction , peptide sequence , biochemistry , transcription factor , gene , membrane , enzyme
CD40 is a member of the tumor necrosis factor receptor (TNF‐R) family that regulates B‐lymphocyte proliferation, immunoglobulin class‐switching, and apoptosis through poorly defined signal transduction mechanisms. Using a yeast two‐hybrid method, cDNAs were obtained that encode a novel protein, CD40‐associated protein‐1 (CAP‐1), which binds specifically to the cytosolic domain of CD40 but not TNF‐R1, TNF‐R2, or Fas. The CAP‐1 protein contains a C‐terminal domain that shares strong amino acid sequence homology with a unique domain found recently in two putative signal transducing proteins that bind to the TNF‐R2 cytosolic tail, TRAF1 and TRAF2. This C‐terminal region of CAP‐1 was sufficient to mediate binding to CD40 and homodimerization of CAP‐1 proteins. The N‐terminal portion of CAP‐1 contains a RING finger motif and three zinc finger‐like domains similar to those found in several regulatory proteins that interact with DNA or RNA. CAP‐1 thus represents a new member of a family of potential signal transducing proteins that contain a conserved domain (the TRAF domain), bind to the cytosolic regions of particular members of TNF‐R family proteins, and that can form homo‐ and heterotypic dimers.