myosin type i


Summary: A subclass of myosins found generally associated with actin-rich membrane structures such as filopodia. Members of the myosin type I family are ubiquitously expressed in eukaryotes. The heavy chains of myosin type I lack coiled-coil forming sequences in their tails and therefore do not dimerize.

Top Publications

  1. Chen X, Leto D, Chiang S, Wang Q, Saltiel A. Activation of RalA is required for insulin-stimulated Glut4 trafficking to the plasma membrane via the exocyst and the motor protein Myo1c. Dev Cell. 2007;13:391-404 pubmed
    ..Thus, RalA serves two functions in insulin action: as a cargo receptor for the Myo1c motor, and as a signal for the unification of the exocyst to target Glut4 vesicles to the plasma membrane. ..
  2. Goodson H, Anderson B, Warrick H, Pon L, Spudich J. Synthetic lethality screen identifies a novel yeast myosin I gene (MYO5): myosin I proteins are required for polarization of the actin cytoskeleton. J Cell Biol. 1996;133:1277-91 pubmed
    ..These results indicate that MYO3 and MYO5 encode classical myosin I proteins with overlapping functions and suggest a role for Myo3p and Myo5p in organization of the actin cytoskeleton of Saccharomyces cerevisiae. ..
  3. Fan Y, Eswarappa S, Hitomi M, Fox P. Myo1c facilitates G-actin transport to the leading edge of migrating endothelial cells. J Cell Biol. 2012;198:47-55 pubmed publisher
    ..In addition, there is no obvious requirement for myosin II contractile-based transport of G-actin in ECs. Thus, Myo1c-facilitated G-actin transport might be a critical node for control of cell polarity and motility...
  4. de Lanerolle P, Johnson T, Hofmann W. Actin and myosin I in the nucleus: what next?. Nat Struct Mol Biol. 2005;12:742-6 pubmed
    ..We propose highly speculative models and mechanisms solely to stimulate thought and experimentation in this area. ..
  5. Almeida C, Yamada A, Tenza D, Louvard D, Raposo G, Coudrier E. Myosin 1b promotes the formation of post-Golgi carriers by regulating actin assembly and membrane remodelling at the trans-Golgi network. Nat Cell Biol. 2011;13:779-89 pubmed publisher
    ..Our results provide evidence that actin and myosin 1 regulate organelle shape and uncover an important function for myosin 1b in the initiation of post-Golgi carrier formation by regulating actin assembly and remodelling TGN membranes. ..
  6. Nakamori Y, Emoto M, Fukuda N, Taguchi A, Okuya S, Tajiri M, et al. Myosin motor Myo1c and its receptor NEMO/IKK-gamma promote TNF-alpha-induced serine307 phosphorylation of IRS-1. J Cell Biol. 2006;173:665-71 pubmed
    ..Thus, motor protein Myo1c and its receptor protein NEMO act cooperatively to form the IKK-IRS-1 complex and function in TNF-alpha-induced insulin resistance. ..
  7. Tyska M, Mooseker M. MYO1A (brush border myosin I) dynamics in the brush border of LLC-PK1-CL4 cells. Biophys J. 2002;82:1869-83 pubmed
    ..This rapidly exchanging pool of M1A envelops an actin core bundle that, by comparison, is static in structure. ..
  8. Crawley S, De La Roche M, Lee S, Li Z, Chitayat S, Smith S, et al. Identification and characterization of an 8-kDa light chain associated with Dictyostelium discoideum MyoB, a class I myosin. J Biol Chem. 2006;281:6307-15 pubmed
    ..We conclude that MlcB represents a novel type of small myosin light chain that binds to IQ motifs in a manner comparable with a single lobe of a typical four-EF-hand protein. ..
  9. Barylko B, Jung G, Albanesi J. Structure, function, and regulation of myosin 1C. Acta Biochim Pol. 2005;52:373-80 pubmed
    ..The search for these putative myosin 1C receptors is an active area of research. ..

More Information


  1. Lechler T, Jonsdottir G, Klee S, Pellman D, Li R. A two-tiered mechanism by which Cdc42 controls the localization and activation of an Arp2/3-activating motor complex in yeast. J Cell Biol. 2001;155:261-70 pubmed
    ..Together, these findings provide insights into the essential processes leading to polarization of the actin cytoskeleton. ..
  2. El Mezgueldi M, Tang N, Rosenfeld S, Ostap E. The kinetic mechanism of Myo1e (human myosin-IC). J Biol Chem. 2002;277:21514-21 pubmed
    ..We propose that subclass-1 myosin-Is are tuned for rapid sliding, whereas subclass-2 isoforms are tuned for tension maintenance or stress sensing. ..
  3. Bose A, Guilherme A, Robida S, Nicoloro S, Zhou Q, Jiang Z, et al. Glucose transporter recycling in response to insulin is facilitated by myosin Myo1c. Nature. 2002;420:821-4 pubmed
    ..Thus, myosin Myo1c functions in a PI(3)K-independent insulin signalling pathway that controls the movement of intracellular GLUT4-containing vesicles to the plasma membrane. ..
  4. Ye J, Zhao J, Hoffmann Rohrer U, Grummt I. Nuclear myosin I acts in concert with polymeric actin to drive RNA polymerase I transcription. Genes Dev. 2008;22:322-30 pubmed publisher
    ..These observations provide insights into the cooperative action of actin and myosin in the nucleus and reveal an actomyosin-based mechanism in transcription. ..
  5. Gillespie P, Cyr J. Calmodulin binding to recombinant myosin-1c and myosin-1c IQ peptides. BMC Biochem. 2002;3:31 pubmed
    ..The calmodulin bound to one of these IQ domains, probably IQ2, is only weakly associated. Upon Ca2+ elevation, all calmodulin except that bound to IQ3 should dissociate. ..
  6. Hokanson D, Ostap E. Myo1c binds tightly and specifically to phosphatidylinositol 4,5-bisphosphate and inositol 1,4,5-trisphosphate. Proc Natl Acad Sci U S A. 2006;103:3118-23 pubmed
    ..Our results suggest that myo1c does not bind to physiological concentrations of PS but rather binds tightly to PIP(2). ..
  7. Falk D, Wessels D, Jenkins L, Pham T, Kuhl S, Titus M, et al. Shared, unique and redundant functions of three members of the class I myosins (MyoA, MyoB and MyoF) in motility and chemotaxis in Dictyostelium. J Cell Sci. 2003;116:3985-99 pubmed
    ..Interestingly, the combined defects of the myosin I mutants are similar to those of a single mutant with constitutive PKA activity, suggesting that PKA plays a role in the regulation of all three class I myosins. ..
  8. Tang N, Lin T, Ostap E. Dynamics of myo1c (myosin-ibeta ) lipid binding and dissociation. J Biol Chem. 2002;277:42763-8 pubmed
    ..Calcium significantly increases the lifetimes of the membrane-bound state, resulting in dissociation rates 0.001 s(-1). ..
  9. Dzijak R, Yildirim S, Kahle M, Novak P, Hnilicová J, Venit T, et al. Specific nuclear localizing sequence directs two myosin isoforms to the cell nucleus in calmodulin-sensitive manner. PLoS ONE. 2012;7:e30529 pubmed publisher
    ..This opens a new field for exploring functions of this molecular motor in nuclear processes, and for exploring the signals between cytoplasm and the nucleus. ..
  10. Kahle M, Pridalová J, Spacek M, Dzijak R, Hozak P. Nuclear myosin is ubiquitously expressed and evolutionary conserved in vertebrates. Histochem Cell Biol. 2007;127:139-48 pubmed
    ..The analysis of genomic sequences indicates that almost identical homologous NMI genes are expressed in mammals, and similar NMI genes in vertebrates. ..
  11. Toyoda T, An D, Witczak C, Koh H, Hirshman M, Fujii N, et al. Myo1c regulates glucose uptake in mouse skeletal muscle. J Biol Chem. 2011;286:4133-40 pubmed publisher
    ..Myo1c is a novel mediator of both insulin-stimulated and contraction-stimulated glucose uptake in skeletal muscle. ..
  12. Lin T, Greenberg M, Moore J, Ostap E. A hearing loss-associated myo1c mutation (R156W) decreases the myosin duty ratio and force sensitivity. Biochemistry. 2011;50:1831-8 pubmed publisher
    ..Taken together, these results indicate that myo1c with the R156W mutation has a lower duty ratio than the wild-type protein and motile properties that are less sensitive to resisting forces. ..
  13. Arif E, Wagner M, Johnstone D, Wong H, George B, Pruthi P, et al. Motor protein Myo1c is a podocyte protein that facilitates the transport of slit diaphragm protein Neph1 to the podocyte membrane. Mol Cell Biol. 2011;31:2134-50 pubmed publisher
    ..These results identify a novel Myo1c-dependent molecular mechanism that mediates the dynamic organization of Neph1 and nephrin at the slit diaphragm and is critical for podocyte function. ..
  14. Diefenbach T, Latham V, Yimlamai D, Liu C, Herman I, Jay D. Myosin 1c and myosin IIB serve opposing roles in lamellipodial dynamics of the neuronal growth cone. J Cell Biol. 2002;158:1207-17 pubmed
    ..Thus, M1c and MIIB serve opposite and nonredundant roles in regulating lamellipodial dynamics, and M1c activity is specifically required for retrograde F-actin flow. ..
  15. Bose A, Robida S, Furcinitti P, Chawla A, Fogarty K, Corvera S, et al. Unconventional myosin Myo1c promotes membrane fusion in a regulated exocytic pathway. Mol Cell Biol. 2004;24:5447-58 pubmed
    ..Thus, localized membrane remodeling driven by the Myo1c motor appears to facilitate the fusion of exocytic GLUT4-containing vesicles with the adipocyte plasma membrane. ..
  16. Sokac A, Schietroma C, Gundersen C, Bement W. Myosin-1c couples assembling actin to membranes to drive compensatory endocytosis. Dev Cell. 2006;11:629-40 pubmed
    ..Remarkably, there is also an increase in polymerized actin at membranes throughout the cell. We conclude that XlMyo1c couples polymerizing actin to membranes and so mediates force production during compensatory endocytosis. ..
  17. McKenna J, Ostap E. Kinetics of the interaction of myo1c with phosphoinositides. J Biol Chem. 2009;284:28650-9 pubmed publisher
  18. Gillespie P. Myosin I and adaptation of mechanical transduction by the inner ear. Philos Trans R Soc Lond B Biol Sci. 2004;359:1945-51 pubmed
    ..The sliding-filament hypothesis for muscle contraction has thus led to a detailed understanding of the behaviour of hair cells. ..
  19. Kysela K, Philimonenko A, Philimonenko V, Janacek J, Kahle M, Hozak P. Nuclear distribution of actin and myosin I depends on transcriptional activity of the cell. Histochem Cell Biol. 2005;124:347-58 pubmed
    ..These results demonstrate that actin and NMI are compartmentalized in the nuclei where they can dynamically translocate depending on transcriptional activity of the cells. ..
  20. Salas Cortes L, Ye F, Tenza D, Wilhelm C, Theos A, Louvard D, et al. Myosin Ib modulates the morphology and the protein transport within multi-vesicular sorting endosomes. J Cell Sci. 2005;118:4823-32 pubmed
    ..All together, these observations suggest that myosin 1b controls the traffic of protein cargo in multivesicular endosomes most probably through its ability to modulate with actin the morphology of these sorting endosomes. ..
  21. D Agostino J, Goode B. Dissection of Arp2/3 complex actin nucleation mechanism and distinct roles for its nucleation-promoting factors in Saccharomyces cerevisiae. Genetics. 2005;171:35-47 pubmed
    ..In support of this model, Abp1 binds strongly to Arp2/3 complex, yet has notably weak nucleation-promoting activity and inhibits Las17 activity on Arp2/3 complex in a dose-responsive manner. ..
  22. Laakso J, Lewis J, Shuman H, Ostap E. Myosin I can act as a molecular force sensor. Science. 2008;321:133-6 pubmed publisher
    ..2) to a high (>0.9) duty-ratio motor. This impressive tension sensitivity supports a role for myosin I as a molecular force sensor. ..
  23. Yip M, Ramm G, Larance M, Hoehn K, Wagner M, Guilhaus M, et al. CaMKII-mediated phosphorylation of the myosin motor Myo1c is required for insulin-stimulated GLUT4 translocation in adipocytes. Cell Metab. 2008;8:384-98 pubmed publisher
    ..These data suggest that insulin regulates Myo1c function via CaMKII-dependent phosphorylation, and these events play a role in insulin-regulated GLUT4 trafficking in adipocytes likely involving Myo1c motor activity. ..
  24. de la Roche M, Mahasneh A, Lee S, Rivero F, Côté G. Cellular distribution and functions of wild-type and constitutively activated Dictyostelium PakB. Mol Biol Cell. 2005;16:238-47 pubmed
    ..PakB-null cells displayed no significant behavioral defects, but cells expressing activated PakB were unable to complete cytokinesis when grown in suspension and exhibited increased rates of phagocytosis and pinocytosis. ..
  25. Dürrwang U, Fujita Becker S, Erent M, Kull F, Tsiavaliaris G, Geeves M, et al. Dictyostelium myosin-IE is a fast molecular motor involved in phagocytosis. J Cell Sci. 2006;119:550-8 pubmed
    ..Changes in the level of free Mg(2+) ions, which are within the physiological range, are shown to modulate the motor activity of myosin-IE by inhibiting the release of adenosine diphosphate. ..
  26. Sirotkin V, Beltzner C, Marchand J, Pollard T. Interactions of WASp, myosin-I, and verprolin with Arp2/3 complex during actin patch assembly in fission yeast. J Cell Biol. 2005;170:637-48 pubmed
    ..Genetic dependencies of patch formation suggest that patch formation involves cross talk between Myo1p and Wsp1p/Vrp1p pathways. ..
  27. Wu C, Lytvyn V, Thomas D, Leberer E. The phosphorylation site for Ste20p-like protein kinases is essential for the function of myosin-I in yeast. J Biol Chem. 1997;272:30623-6 pubmed
    ..Our results suggest that phosphorylation of the head domain by Ste20p-like protein kinases plays an essential role in the function of myosin-I in yeast cells. ..
  28. Higgs H, Pollard T. Regulation of actin filament network formation through ARP2/3 complex: activation by a diverse array of proteins. Annu Rev Biochem. 2001;70:649-76 pubmed
    ..These interactions provide a final common pathway for many signaling inputs to regulate actin polymerization. Microorganisms either activate Arp2/3 complex directly or usurp N-WASP to initiate actin polymerization. ..
  29. Stauffer E, Scarborough J, Hirono M, Miller E, Shah K, Mercer J, et al. Fast adaptation in vestibular hair cells requires myosin-1c activity. Neuron. 2005;47:541-53 pubmed
    ..These results suggest that mechanical activity of myosin-1c is required for fast adaptation in vestibular hair cells. ..
  30. Vintermist A, Böhm S, Sadeghifar F, Louvet E, Mansén A, Percipalle P, et al. The chromatin remodelling complex B-WICH changes the chromatin structure and recruits histone acetyl-transferases to active rRNA genes. PLoS ONE. 2011;6:e19184 pubmed publisher
    ..We propose that the B-WICH complex remodels the chromatin structure at actively transcribed rRNA genes, and this allows for the association of specific histone acetyl-transferases. ..
  31. Machesky L. The tails of two myosins. J Cell Biol. 2000;148:219-21 pubmed
  32. Oberholzer U, Iouk T, Thomas D, Whiteway M. Functional characterization of myosin I tail regions in Candida albicans. Eukaryot Cell. 2004;3:1272-86 pubmed
    ..Among the six myosin I tail domain mutants, the ability to form hyphae was strictly correlated with endocytosis. We propose that the uptake of cell wall remodeling enzymes and excess plasma membrane is critical for hyphal formation. ..
  33. Bretschneider T, Anderson K, Ecke M, Müller Taubenberger A, Schroth Diez B, Ishikawa Ankerhold H, et al. The three-dimensional dynamics of actin waves, a model of cytoskeletal self-organization. Biophys J. 2009;96:2888-900 pubmed publisher
    ..These data show that force-generating, highly organized supramolecular networks are autonomously formed in live cells from molecular motors and proteins controlling actin polymerization and depolymerization. ..
  34. McGoldrick C, Gruver C, May G. myoA of Aspergillus nidulans encodes an essential myosin I required for secretion and polarized growth. J Cell Biol. 1995;128:577-87 pubmed
    ..Under repressing conditions, this strain also displays reduced levels of secreted acid phosphatase. The mutant phenotype indicates that myoA plays a critical role in polarized growth and secretion. ..
  35. Zadro C, Alemanno M, Bellacchio E, Ficarella R, Donaudy F, Melchionda S, et al. Are MYO1C and MYO1F associated with hearing loss?. Biochim Biophys Acta. 2009;1792:27-32 pubmed publisher
    ..This study suggests a role of the above mentioned myosin genes in the pathogenesis of hearing loss. ..
  36. Obrdlik A, Louvet E, Kukalev A, Naschekin D, Kiseleva E, Fahrenkrog B, et al. Nuclear myosin 1 is in complex with mature rRNA transcripts and associates with the nuclear pore basket. FASEB J. 2010;24:146-57 pubmed publisher
    ..We conclude that NM1 facilitates maturation and accompanies export-competent preribosomal subunits to the NPC, thus modulating export. ..
  37. Dumont R, Zhao Y, Holt J, Bähler M, Gillespie P. Myosin-I isozymes in neonatal rodent auditory and vestibular epithelia. J Assoc Res Otolaryngol. 2002;3:375-89 pubmed
    ..Myo1c therefore remains the myosin isozyme best localized to carry out transducer adaptation. ..
  38. Hokanson D, Laakso J, Lin T, Sept D, Ostap E. Myo1c binds phosphoinositides through a putative pleckstrin homology domain. Mol Biol Cell. 2006;17:4856-65 pubmed
    ..This region is not phosphoinositide specific, but it binds anionic phospholipids in a calcium-dependent manner. However, this site is not essential for in vivo membrane binding. ..
  39. Cyr J, Dumont R, Gillespie P. Myosin-1c interacts with hair-cell receptors through its calmodulin-binding IQ domains. J Neurosci. 2002;22:2487-95 pubmed
    ..The calcium-sensitive binding of calmodulin to myosin-1c may therefore modulate the interaction of the adaptation motor with other components of the transduction apparatus. ..
  40. Mele C, Iatropoulos P, Donadelli R, Calabria A, Maranta R, Cassis P, et al. MYO1E mutations and childhood familial focal segmental glomerulosclerosis. N Engl J Med. 2011;365:295-306 pubmed publisher
    ..Our data provide evidence of a role of Myo1E in podocyte function and the consequent integrity of the glomerular filtration barrier. ..
  41. Geli M, Lombardi R, Schmelzl B, Riezman H. An intact SH3 domain is required for myosin I-induced actin polymerization. EMBO J. 2000;19:4281-91 pubmed
  42. Philimonenko V, Janacek J, Harata M, Hozak P. Transcription-dependent rearrangements of actin and nuclear myosin I in the nucleolus. Histochem Cell Biol. 2010;134:243-9 pubmed publisher
    ..Our data support the involvement of actin and NMI in rDNA transcription and point out to other functions of these proteins in the nucleolus, such as rRNA maturation and maintenance of nucleolar architecture. ..
  43. Jonsdottir G, Li R. Dynamics of yeast Myosin I: evidence for a possible role in scission of endocytic vesicles. Curr Biol. 2004;14:1604-9 pubmed
    ..Based on these results, we hypothesize that the myosin I motor protein facilitates the membrane fusion/vesicle scission event of endocytosis. ..
  44. Manceva S, Lin T, Pham H, Lewis J, Goldman Y, Ostap E. Calcium regulation of calmodulin binding to and dissociation from the myo1c regulatory domain. Biochemistry. 2007;46:11718-26 pubmed
    ..Our data suggest that the calmodulin bound to the IQ motif adjacent to the motor domain is rapidly exchangeable in the presence of calcium and is responsible for regulation of myo1c ATPase and motile activity. ..
  45. Gillespie P, Albanesi J, Bahler M, Bement W, Berg J, Burgess D, et al. Myosin-I nomenclature. J Cell Biol. 2001;155:703-4 pubmed
    ..Despite their faults, we believe that the names adopted by the HUGO nomenclature group for genome annotation are the best compromise, and we recommend universal adoption. ..
  46. Schwarz E, Neuhaus E, Kistler C, Henkel A, Soldati T. Dictyostelium myosin IK is involved in the maintenance of cortical tension and affects motility and phagocytosis. J Cell Sci. 2000;113 ( Pt 4):621-33 pubmed
    ..At early stages of development, aggregation of myoK null cells was slowed due to reduced motility. Altogether, the data indicate a distinctive role for MyoK in the maintenance and dynamics of the cell cortex. ..
  47. Hofmann W, Johnson T, Klapczynski M, Fan J, de Lanerolle P. From transcription to transport: emerging roles for nuclear myosin I. Biochem Cell Biol. 2006;84:418-26 pubmed
    ..Moreover, this movement is based on an active and directed process that is facilitated by an acto-NMI complex, establishing for the first time a functional role for a motor complex consisting of actin and a myosin in the nucleus. ..
  48. Anderson B, Boldogh I, Evangelista M, Boone C, Greene L, Pon L. The Src homology domain 3 (SH3) of a yeast type I myosin, Myo5p, binds to verprolin and is required for targeting to sites of actin polarization. J Cell Biol. 1998;141:1357-70 pubmed
    ..Our studies support a multistep model for Myo5p targeting in yeast. The first step, assembly of Myo5p patches, is dependent upon F-actin, and the second step, polarization of actin patches, requiresVrp1p and the SH3 domain of Myo5p. ..
  49. Idrissi F, Grötsch H, Fernandez Golbano I, Presciatto Baschong C, Riezman H, Geli M. Distinct acto/myosin-I structures associate with endocytic profiles at the plasma membrane. J Cell Biol. 2008;180:1219-32 pubmed publisher
    ..We also find that in the longest profiles, actin and the myosin-I Myo5p form two distinct structures that might be implicated in vesicle fission. ..
  50. Ruppert C, Godel J, Muller R, Kroschewski R, Reinhard J, Bahler M. Localization of the rat myosin I molecules myr 1 and myr 2 and in vivo targeting of their tail domains. J Cell Sci. 1995;108 ( Pt 12):3775-86 pubmed
    ..These results suggest that the tail domains of myr 1 and myr 2 are sufficient for subcellular targeting but that their head domains also contribute significantly to maintaining a proper subcellular localization. ..
  51. Greenberg M, Ostap E. Regulation and control of myosin-I by the motor and light chain-binding domains. Trends Cell Biol. 2013;23:81-9 pubmed publisher
    ..Here we review the regulation of myosin-I function and localization by the motor and LCBDs. ..
  52. Sun Y, Martin A, Drubin D. Endocytic internalization in budding yeast requires coordinated actin nucleation and myosin motor activity. Dev Cell. 2006;11:33-46 pubmed
    ..These results reveal a mechanism in which actin nucleation and myosin motor activity cooperate to promote endocytic internalization. ..
  53. Philimonenko V, Zhao J, Iben S, Dingová H, Kysela K, Kahle M, et al. Nuclear actin and myosin I are required for RNA polymerase I transcription. Nat Cell Biol. 2004;6:1165-72 pubmed
    ..The association with Pol I requires phosphorylation of TIF-IA at Ser 649 by RSK kinase, indicating a role for NMI in the growth-dependent regulation of rRNA synthesis. ..