what kind of accessory protein would you classify IRS1 and 2 as? Docking protein Adaptor protein? Transcription factor? SH2 domain protein Solution Docking protein - The robosomes are of two types based on their occurence in the cell. Free ribosomes and membrane bound (on ER surface). Ever wondered why and how they are of two types? Yes!! Some specific proteins which are found on the surface of certain specific ribosomal particles making them \"dock\" (stick) on to the ER surface are called docking proteins. Adapter protein - An adapter protein is one which assists in signal transduction across membranes. They aid receptor mechanisms in the cells. Transcription factor - The process of copying cell DNA codons in to an mRNA strand in called transcription. This is assisted by certain types of protein called Transcription factors. SH2 domain - These are specific proteins that mediate and fecilitate protein-protein inteactions in the cell. SH2 domain (a structurally special part within a protein molecule) is found within Src oncoprotein (cancer protein) which makes the Src oncoprotein attach to other protein containing phosphorylated tyrosin residues. **IRS1 and IRS2 proteins are classified as adapter proteins.**.