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Myosin IIA drives membrane bleb retraction


Taneja NNilay , Burnette DTDylan T . Molecular biology of the cell. 2019 02 20; (). mbcE18110752


Membrane blebs are specialized cellular protrusions that play diverse roles in processes such as cell division and cell migration. Blebbing can be divided into three distinct phases- bleb nucleation, bleb growth and bleb retraction. Following nucleation and bleb growth, the actin cortex, comprising actin, cross-linking proteins and non-muscle myosin II (MII), begins to re-assemble on the membrane. MII then drives the final phase, bleb retraction, which results in re-integration of the bleb into the cellular cortex. There are three MII paralogs with distinct biophysical properties expressed in mammalian cells: MIIA, MIIB and MIIC. Here we show that MIIA specifically drives bleb retraction during cytokinesis. The motor domain and regulation of the non-helical tailpiece of MIIA both contribute to its ability to drive bleb retraction. These experiments have also revealed a relationship between faster turnover of MIIA at the cortex and its ability to drive bleb retraction.