The IRS4 (Insulin Receptor Substrate 4) protein is a signaling adaptor molecule involved in the insulin and IGF-1 receptor signaling pathways. Known binding partners for IRS4 include:

1. Insulin Receptor (IR): IRS4 binds to the activated insulin receptor, playing a role in insulin signal transduction.

2. IGF-1 Receptor (IGF1R): Similarly to the insulin receptor, IRS4 can interact with the IGF-1 receptor.

3. Phosphoinositide 3-kinases (PI3Ks): These are lipid kinases involved in signaling pathways, and IRS4 helps in propagating signals leading to cell growth and metabolism regulation.

4. Grb2 (Growth factor receptor-bound protein 2): It is an adaptor protein that links IRS4 to downstream signaling pathways.

5. SH2 domain-containing proteins: Many of these proteins can interact with phosphorylated tyrosine residues on IRS4, including SHP2 (Src homology region 2 domain-containing phosphatase-2).

These interactions help in regulating various cellular processes such as growth, metabolism, and survival. The specific set of binding partners may vary depending on the cellular context and the presence of post-translational modifications on IRS4.

For further detailed insights into IRS4 and its binding partners, you may find it useful to search scientific literature databases such as PubMed.