title: A novel Src homology 2 domain-containing molecule, Src-like adapter protein-2 (SLAP-2), which negatively regulates T cell receptor signaling.
abstract: We have cloned a novel adapter protein containing Src homology 2 and Src homology 3 domains similar to the Src family of tyrosine kinases. This molecule lacks a catalytic tyrosine kinase domain and is related to a previously identified protein, Src-like adapter protein (SLAP), and is therefore designated SLAP-2. Northern blot analysis indicates that SLAP-2 is predominantly expressed in the immune system. Jurkat T cells express SLAP-2 protein and overexpression of SLAP-2 in these cells negatively regulates T cell receptor signaling as assessed by interleukin-2 promoter or NF-AT promoter reporter constructs. Mutational analysis revealed that an intact SH2 domain of SLAP-2 is essential for this inhibitory effect, whereas mutation of the SH3 domain alone has no effect. This inhibitory effect is upstream of the activation of Ras and increase of intracellular calcium levels, as no inhibition was observed when the cells were activated by phorbol ester plus ionomycin. SLAP-2 interacts with Cbl in vivo in a phosphorylation independent manner and with ZAP-70 and T cell receptor zeta chain upon T cell receptor activation. Finally, we show that the mutation of a predicted myristoylation site within the NH(2)-terminal of SLAP-2 is essential for its inhibitory effect. This report therefore implicates SLAP and SLAP-2 as a family of adapter proteins that negatively regulate T cell receptor signaling.
authors.affiliation: Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Pandey
authors.forename: Nieves
authors.initials: N
authors.lastname: Ibarrola
authors.forename: Irina
authors.initials: I
authors.lastname: Kratchmarova
authors.forename: Minerva M
authors.initials: MM
authors.lastname: Fernandez
authors.forename: Stefan N
authors.initials: SN
authors.lastname: Constantinescu
authors.forename: Osamu
authors.initials: O
authors.lastname: Ohara
authors.forename: Sansana
authors.initials: S
authors.lastname: Sawasdikosol
authors.forename: Harvey F
authors.initials: HF
authors.lastname: Lodish
authors.forename: Matthias
authors.initials: M
authors.lastname: Mann
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D019814:Myristic Acid / Q000378:metabolism; D010766:Phosphorylation; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018076:DNA, Complementary; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell; C441328:SLA2 protein, human; D019814:Myristic Acid; D014443:Tyrosine; D016392:Proto-Oncogene Proteins pp60(c-src)