Burnette Lab

Myosin IIA drives membrane bleb retraction

AUTHORS

ABSTRACT

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.