SLA

SLA (hSLAP) is a Src-like adaptor protein that contains SH3 and SH2 domains but lacks a tyrosine kinase catalytic domain, structurally resembling Src family kinases while acting as an adaptor rather than an enzyme (PMID:9660183). The gene is embedded within the largest intron of the thyroglobulin gene on chromosome 8q24 and is transcribed in the opposite orientation, with highest expression detected in fetal brain and lung and two alternatively spliced isoforms (PMID:9660183). In acute lymphoblastic leukemia cells, SLA is a prominent glucocorticoid response gene, but neither its overexpression nor its knockdown alters cell survival, cell cycle progression, or sensitivity to glucocorticoid-induced apoptosis, indicating it does not mediate the anti-leukemic effects of glucocorticoids in this context (PMID:19631983). Beyond its domain architecture and this negative functional result, the receptor-signaling role of SLA is largely uncharacterized in the available corpus.

1. 1995 Low

   Establishing where SLA lies in the genome and that it is an adaptor rather than a kinase framed it as a potential modulator of receptor tyrosine kinase signaling.

   Evidence Linkage analysis and somatic cell hybrid panel mapping placing mouse Slap on chromosome 15 and human SLA on 8q22.3-qter, with domain characterization

   PMID:8825655

   Open questions at the time

   • Eck receptor binding was cited from prior work, not directly demonstrated here
   • no functional consequence of the adaptor–receptor interaction tested
   • mapping resolution did not define the precise locus relationship later refined
2. 1998 Medium

   Cloning the human gene defined its protein product, isoforms, and unusual genomic embedding, providing the molecular foundation for any mechanistic study.

   Evidence Exon trapping, cDNA cloning from a fetal brain library, Northern blot, and sequence analysis

   PMID:9660183

   Open questions at the time

   • no mechanistic or interaction experiments performed
   • functional significance of the two splice isoforms unknown
   • biological role of fetal brain/lung enrichment not addressed
3. 2009 Medium

   Testing whether SLA, a strong glucocorticoid-induced transcript, drives steroid-induced leukemic cell death resolved a candidate mechanism by ruling it out.

   Evidence Overexpression and siRNA knockdown in ALL cell lines with viability, cell cycle, and apoptosis readouts

   PMID:19631983

   Open questions at the time

   • negative result does not exclude roles in other cell types or signaling contexts
   • direct molecular targets or partners of SLA not identified
   • reason for its strong glucocorticoid induction left unexplained

• The direct molecular function of SLA — which receptors or substrates it engages through its SH3/SH2 domains and what downstream signaling it modulates — remains undefined in the available corpus.
• no validated physical partner demonstrated in human cells
• no signaling pathway directly attributed to SLA
• physiological function in fetal brain/lung uncharacterized