{HEAD ~ IRS1} and IRS2 are {TAIL ~ part} of the insulin or insulin like growth factor signaling pathways, but also mediate some signals through other growth factors and cytokines, including IFNγ, IL2, IL4, IL7, IL9, IL13 or IL15, growth hormone, prolactin, or leptin 
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{ HEAD ~ IRS1 } and IRS2 are { TAIL ~ part } of the insulin or insulin like growth factor signaling pathways , but also mediate some signals through other growth factors and cytokines , including IFNγ , IL2 , IL4 , IL7 , IL9 , IL13 or IL15 , growth hormone , prolactin , or leptin
HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH