PAK1 and breast carcinoma: One study also investigated the effects of HGF on STMN1 phosphorylation in MDA-MB-231 human breast cancer cells and determined that HGF (50 ng/mL) promoted STMN1 phosphorylation at S25 and S38, which induced microtubule growth, STMN1 binding to the Pak1–WAVE2–kinesin complex via the selective phosphorylation of S38, and lamellipodia formation [16,17,18].