IRS1 and IRS2 are {HEAD ~ part} of {TAIL ~ the insulin} or insulin like growth factor signaling pathway 
of
IRS1 and IRS2 are { HEAD ~ part } of { TAIL ~ the insulin } or insulin like growth factor signaling pathway
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH