Myosin Superfamily


Myosins are a large family of actin‐based mechanoenzymes that bind and hydrolyse ATP to generate the force and movement along actin filaments necessary to drive a wide variety of cellular functions. Phylogenetic analysis has so far identified 17 distinct classes of myosin (designated I–XVII).

Keywords: myosin I; myosin II; myosin V; myosins VI, VII, XV; plant myosins VIII, XI, XIII

Figure 1.

An unrooted phylogenetic tree of the myosin superfamily. The tree is derived from an alignment of 145 members of the myosin superfamily. This alignment compares the core motor domains (equivalent to amino acids 88–780 of chicken skeletal myosin II) of each myosin using distance matrix analysis performed with the Clustal‐W package. The exceptions, shown with a dotted line, are SsVIIa, a partial sequence in the databases and Hs MysPDZ, which has a truncated amino end starting some 52 residues into the core motor region. Gap positions in the alignment were included during bootstrap analysis (repeated redrawing of the tree structure to yield confidence estimates) in order not to exclude a large proportion of the data. Being unrooted, the relationships between classes as shown by the branching order at the centre of the tree are unreliable but evolutionary information can be derived within a class. The molecular cartoons serve to indicate possible molecular structure, especially the expected single or double headed nature of the myosins.

Figure 2.

Myosin domain structure as predicted from sequence analysis. The predicted functional domains identified in the various myosin classes are shown graphically for representatives of each class. The protein sequence bars and domain sizes are only approximately to scale; hence no scale is given. Note the motor domains are relatively conserved whereas the tail domains are highly variable. Those regions in the tails in white (blank) are those so far without any recognizable homologies.



Bahler M (2000) Are class III and class IX myosins motorised signalling molecules? Biochimica et Biophysica Acta 1496: 52–59.

Baker JP and Titus MA (1997) A family of unconventional myosins from the nematode Caenorhabditis elegans. Journal of Molecular Biology 172: 523–535.

Barylko B, Binns DD and Albanesi JP (2000) Regulation of the enzymatic and motor activities of myosin I. Biochimica et Biophysica Acta 1496: 23–35.

Coluccio LM (1997) Myosin I. American Journal of Physiology 273: 347–359.

Hettmann C, Herm A, Geiter A et al. (2000) A dibasic motif in the tail of a class XIV apicomplexan myosin is an essential determinant of plasma membrane localization. Molecular Biology of the Cell 11: 1385–1400.

Kendrick‐Jones J and Reichelt S (1999) Myosin, plant. In: Kreiss T and Vale R (eds) The Guidebook of Cytoskeletal and Motor Proteins, pp. 457–460. Oxford: Oxford University Press.

Mermall V, Post PL and Mooseker MS (1998) Unconventional myosins in cell movement, membrane traffic and signal transduction. Science 279: 527–533.

Montell C (1999) Visual transduction in Drosophila. Annual Review of Cellular and Developmental Biology 15: 231–268.

Mooseker MS and Cheney RE (1995) Unconventional myosins. Annual Review of Cellular and Developmental Biology 11: 633–675.

Rayment I, Rypniewski WR, Schmidt‐Base K et al. (1993) Three dimensional structure of myosin subfragment‐1: a molecular motor. Science 261: 50–58.

Reck‐Peterson SL, Provance DW Jr, Mooseker MS and Mercer JA (2000) Class V myosins. Biochimica et Biophysica Acta 1496: 36–51.

Sellers JR (2000) Myosins: a diverse superfamily. Biochimica et Biophysica Acta 1496: 3–22.

Wu X, Jung G and Hammer JA III (2000) Functions of unconventional myosins. Current Opinion in Cell Biology 12: 42–51.

Further Reading

Baker JP and Titus MA (1998) Myosins: matching functions with motors. Current Opinion in Cell Biology 10: 80–86.

Brown SS (1997) Myosins in yeast. Current Opinion in Cell Biology 9: 44–48.

Cheney RE and Baker JP (1999) Myosins, divergent. In: Kreiss T and Vale R (eds) The Guidebook of Cytoskeletal and Motor Proteins, pp. 453–456. Oxford: Oxford University Press.

Cooke R (1997) Actomyosin interaction in striated muscle. Physiological Reviews 77(3): 671–697.

Cope MJTV, Whisstock J, Rayment I and Kendrick‐Jones J (1996) Conservation within the myosin motor domain: implications for structure and function. Structure 4: 969–987.

Hasson T (1997) Unconventional myosins, the basis for deafness in mouse and man. American Journal of Human Genetics 61: 801–805.

Holmes KC (1997) The swinging lever arm hypothesis of muscle contraction. Current Biology 7: R112–118.

Millar KG (1999) Myosin VI. In: Kreiss T and Vale R (eds) The Guidebook of Cytoskeletal and Motor Proteins, pp. 445–447. Oxford: Oxford University Press.

Vale RD and Milligan RA (2000) The way things move: looking under the hood of molecular motor proteins. Science 288: 88–95.

Walker ML, Burgess SA, Sellers JR et al. (2000) Two‐headed binding of a processive myosin to F‐actin. Nature 405: 804–807.

Wells AL, Lin AW, Chen LQ et al. (1999) Myosin VI is an actin‐based motor that moves backwards. Nature 401: 505–508.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Kendrick‐Jones, J, Hodge, TP, Lister, IMB, Roberts, RC, and Buss, F(Apr 2001) Myosin Superfamily. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0000673]