The role of Syntaxin-4 N-terminal Peptide Interaction with Munc18c in Adhesion, Migration, and Polarity

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Randall, Connor
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University of Guelph

Tumour cell migration depends on cellular sensing of surrounding extracellular matrix or signaling molecules using receptors at the plasma membrane. Receptor exocytosis relies on soluble N-ethylmaleimide attachment protein receptors (SNAREs) on vesicular and plasma membranes forming a trans-SNARE complex. Sec1/Munc18 (SM) proteins bind syntaxin-family SNAREs and regulate their entry into a trans-SNARE complex. Recently, Munc18c binding to its cognate Syntaxin, Syntaxin-4 (Stx4), was shown to regulate tumour cell migration through an unknown mechanism. Here we show that Munc18c/Stx4 interaction does not regulate cellular attachment to extracellular matrix, or focal adhesion dynamics. Furthermore, Stx4 is recruited to the leading edge independent of its interaction with Munc18c. However, we found inhibiting Munc18c/Stx4 interaction inhibits Golgi repositioning towards the leading edge during scratch-induced migration, suggesting interaction between these two proteins may be necessary for establishment of front-rear polarity. These results contribute to the overall understanding of how membrane trafficking influences cell migration.

Cell Migration, Intracellular Trafficking, Munc18c, Syntaxin-4, Focal Adhesion, Polarity