background:
Sam 68 is a protein that is phosphorylated on tyrosine and functions as a substrate for Src family tyrosine kinases during mitosis. Sam 68 also associates with several SH2 and SH3 domain-containing signaling proteins, such as GRB2 and PLC ?. Originally cloned as Ras GAP-associated p62, further investigations have shown that Sam 68 and Ras GAP-associated p62 are not antigenically related, nor are they encoded by the same gene. Like Sam 68, the Sam 68-like mammalian proteins, SLM-1 and SLM-2, demonstrate RNA binding activity. Also like Sam 68, SLM-1 is tyrosine phosphorylated and functions as an adapter protein for signaling molecules, including GRB2, PLC ?, Fyn and Ras GAP. SLM-2 is not tyrosine phosphorylated, nor does it appear to associate with GRB2, PLC ?, Fyn or Ras GAP, indicating that SLM-2 may not be an adapter protein for these proteins.
Function:
Recruited and tyrosine phosphorylated by several receptor systems, for example the T-cell, leptin and insulin receptors. Once phosphorylated, functions as an adapter protein in signal transduction cascades by binding to SH2 and SH3 domain-containing proteins. Role in G2-M progression in the cell cycle. Represses CBP-dependent transcriptional activation apparently by competing with other nuclear factors for binding to CBP. Also acts as a putative regulator of mRNA stability and/or translation rates and mediates mRNA nuclear export.
Isoform 3, which is expressed in growth-arrested cells only, inhibits S phase.
Subcellular Location:
Nucleus. Membrane.
Tissue Specificity:
Ubiquitously expressed in all tissue examined. Isoform 1 is expressed at lower levels in brain, skeletal muscle, and liver whereas isoform 3 is intensified in skeletal muscle and in liver.
Post-translational modifications:
Tyrosine phosphorylated by several non-receptor tyrosine kinases, for example LCK, FYN and JAK3. Negatively correlates with ability to bind RNA but required for many interactions with proteins.
Acetylated. Positively correlates with ability to bind RNA.
Arginine methylation is required for nuclear localization. Also can affect interaction with other proteins. Inhibits interaction with Src-like SH3 domains, but not interaction with WW domains of WBP4/FBP21 AND FNBP4/FBP30.
Arg-291, Arg-331 and Arg-346 are found to be also dimethylated, probably to asymmetric dimethylarginine.
Similarity:
Belongs to the KHDRBS family.
Contains 1 KH domain.
Database links:
Entrez Gene: 374071 Chicken
Entrez Gene: 10657 Human
Entrez Gene: 20218 Mouse
Entrez Gene: 117268 Rat
Omim: 602489 Human
SwissProt: Q8UUW7 Chicken
SwissProt: Q07666 Human
SwissProt: Q3U8T3 Mouse
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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