1. Definition
Dynamin is a GTPase enzyme (protein) responsible for membrane remodeling during processes like endocytosis and vesicle trafficking.
2. Function
Dynamic plays a certain role in constriction and fusion processes. These are usually concerning the membrane of the Golgi apparatus or the cell membrane. Dynamins also play a role in the division of cell organelles and cytoplasm (cytokinesis) as well as in the defense against microbial pathogens.
3. Biochemistry
The biochemical aspect of Dynamin revolves around its role as a GTPase enzyme that hydrolyzes guanosine triphosphate (GTP) to provide energy for membrane fission events, particularly in the process of endocytosis.
I. GTP Binding: Dynamin binds GTP at its active site, inducing a conformational change that promotes the assembly of dynamin molecules into a helical structure around the neck of a budding vesicle.
II. GTP Hydrolysis: The hydrolysis of GTP into GDP and inorganic phosphate (Pi) provides the energy necessary for dynamin to constrict and sever the membrane.
III. Conformational Change: The energy released from GTP hydrolysis causes a conformational change in the helical dynamin structure, tightening it around the vesicle neck and eventually pinching it off.
4. Isoforms
Dynamin 1 (DNM1) is found in neurons and neuroendocrine cells.
Dynamin 2 is expressed in most cell types
Dynamin 3 is particularly strongly expressed in the testicles, but also in the brain, lungs and heart.
5. Clinic
Mutations in the gene coding for dynamin-1 can probably cause epilepsy and schizophrenia.
Mutations in the gene coding for dynamin-2 can cause rare hereditary myopathies in humans.