Myotubularin functions through actomyosin to interact with the Hippo pathway

Haldol Targets IQGAP1 Pathway and Promotes Novel Partner Interactions in Glioblastoma Cell Lines

Glioblastoma multiform (GBM) is an incurable heterogenous brain cancer with few clinical target options. IQGAP1 is a scaffold oncoprotein involved in GBM with unclear mechanism. Here we report that the antipsychotic drug Haldol differentially alters IQGAP1 signaling and inhibits GBM cell proliferation, thus providing novel molecular signatures for GBM classification and potential targeted therapy in personalized medicine.

Myotubularin functions through actomyosin to interact with the Hippo pathway

The Hippo pathway is an evolutionarily conserved developmental pathway that controls organ size by integrating diverse regulatory inputs, including actomyosin-mediated cytoskeletal tension. Despite established connections between the actomyosin cytoskeleton and the Hippo pathway, the upstream regulation of actomyosin in the Hippo pathway is less defined. Here, we identify the phosphoinositide-3-phosphatase Myotubularin (Mtm) as a novel upstream regulator of actomyosin that functions synergistically with the Hippo pathway during growth control. Mechanistically, Mtm regulates membrane phospholipid PI(3)P dynamics, which, in turn, modulates actomyosin activity through Rab11-mediated vesicular trafficking. We reveal PI(3)P dynamics as a novel mode of upstream regulation of actomyosin and establish Rab11-mediated vesicular trafficking as a functional link between membrane lipid dynamics and actomyosin activation in the context of growth control. Our study also shows that MTMR2, the human counterpart of Drosophila Mtm, has conserved functions in regulating actomyosin activity and tissue growth, providing new insights into the molecular basis of MTMR2-related peripheral nerve myelination and human disorders.