A squeezing cytoskeletal ring maintains hormonal release

29 Jan 2015

Scientists at the Queensland Brain Institute (QBI) have come one step further in understanding how brain and hormone-releasing cells can sustain long-term communication.

The main way brain cells can maintain their function is by recycling some of the surface membrane through a process called “bulk endocytosis”.

During bulk endocytosis, large amount of the surface membrane is internalised to replenish the pools of neurotransmitter-containing vesicles.

QBI scientists have revealed that “bulk endocytosis” also occurs in hormones releasing cells (neuroendocrine) and involves a contractile cytoskeletal ring.

Miss Rachel Gormal, Laboratory Manager of Professor Frederic Meunier’s QBI laboratory and paper co-first author said: “What people did not understand is how the neck of these bulk invaginations of the membrane could reduce their diameter to a size amenable to fission from the surface membrane.”

Professor Frederic Meunier said the new finding, published in The Journal of Neuroscience, reveals that this involves an acto-myosin ring squeezing the neck of the internalised membrane just before fission.

“This is important not only for hormone secreting cells but also for neurons as this mode of endocytosis underpins the sustainability of neurotransmitter release.”