Dyneins are a group of
motor proteins which, unlike most other known motor proteins, actually move toward the (-) end of
intermediate filaments (which are polar). They are exceptionally large proteins (roughly 1000 k
Da). The have two heavy chains and various intermediate and light chains.
Dyneins generally considered either
cytosolic (they move
vesicles and
kinetochores around in the
cytoplasm) or
axonemal (these are the kind that make
flagella, like the tail of
sperm, and
cilia, like those found in the airways of humans (which help sweep out
mucus and other junk from the
lungs, but do not survive in smokers, which is why
smokers sometimes cough up big plugs of mucus), move).
Other motor proteins familys include
Kinesins (which also move on
intermediate filaments) and
Myosins (which move on
microfilaments).