Motor properties of Myosin 5c are modulated by tropomyosin isoforms and inhibited by pentabromopseudilin

We describe the purification and functional characterization of human Myo5c–HMM co–produced either with CaM alone or with CaM and the essential and regulatory light chains Myl6 and Myl12b. We describe the extent to which cofilaments of actin and Tpm1.6, Tpm1.8 or Tpm3.1 alter the maximum actin–activated ATPase and motile activity of the recombinant Myo5c constructs. The small allosteric effector pentabromopseudilin (PBP), which is predicted to bind in a groove close to the actin and nucleotide binding site with a calculated ΔG of −18.44 kcal/mol, inhibits the motor function of Myo5c with a half–maximal concentration of 280 nM. Using immunohistochemical staining, we determined the distribution and exact localization of Myo5c in endothelial and endocrine cells from rat and human tissue. Particular high levels of Myo5c were observed in insulin–producing β–cells located within the pancreatic islets of Langerhans.

Source: Frontiers in Physiology - March 28, 2024 Category: Physiology Source Type: research