Identification and Characterization of Nonmuscle Myosin II-C, a New Member of the Myosin II Family

Abstract

A previously unrecognized nonmuscle myosin II heavy chain (NMHC II), which constitutes a distinct branch of the nonmuscle/smooth muscle myosin II family, has recently been revealed in genome data bases. We characterized the biochemical properties and expression patterns of this myosin. Using nucleotide probes and affinity-purified antibodies, we found that the distribution of NMHC II-C mRNA and protein (MYH14) is widespread in human and mouse organs but is quantitatively and qualitatively distinct from NMHC II-A and II-B. In contrast to NMHC II-A and II-B, the mRNA level in human fetal tissues is substantially lower than in adult tissues. Immunofluorescence microscopy showed distinct patterns of expression for all three NMHC isoforms. NMHC II-C contains an alternatively spliced exon of 24 nucleotides in loop I at a location analogous to where a spliced exon appears in NMHC II-B and in the smooth muscle myosin heavy chain. However, unlike neuron-specific expression of the NMHC II-B insert, the NMHC II-C inserted isoform has widespread tissue distribution. Baculovirus expression of noninserted and inserted NMHC II-C heavy meromyosin (HMM II-C/HMM II-C1) resulted in significant quantities of expressed protein (mg of protein) for HMM II-C1 but not for HMM II-C. Functional characterization of HMM II-C1 by actin-activated MgATPase activity demonstrated a Vmax of 0.55 + 0.18 s–1, which was half-maximally activated at an actin concentration of 16.5 + 7.2 μm. HMM II-C1 translocated actin filaments at a rate of 0.05 + 0.011 μm/s in the absence of tropomyosin and at 0.072 + 0.019 μm/s in the presence of tropomyosin in an in vitro motility assay. A previously unrecognized nonmuscle myosin II heavy chain (NMHC II), which constitutes a distinct branch of the nonmuscle/smooth muscle myosin II family, has recently been revealed in genome data bases. We characterized the biochemical properties and expression patterns of this myosin. Using nucleotide probes and affinity-purified antibodies, we found that the distribution of NMHC II-C mRNA and protein (MYH14) is widespread in human and mouse organs but is quantitatively and qualitatively distinct from NMHC II-A and II-B. In contrast to NMHC II-A and II-B, the mRNA level in human fetal tissues is substantially lower than in adult tissues. Immunofluorescence microscopy showed distinct patterns of expression for all three NMHC isoforms. NMHC II-C contains an alternatively spliced exon of 24 nucleotides in loop I at a location analogous to where a spliced exon appears in NMHC II-B and in the smooth muscle myosin heavy chain. However, unlike neuron-specific expression of the NMHC II-B insert, the NMHC II-C inserted isoform has widespread tissue distribution. Baculovirus expression of noninserted and inserted NMHC II-C heavy meromyosin (HMM II-C/HMM II-C1) resulted in significant quantities of expressed protein (mg of protein) for HMM II-C1 but not for HMM II-C. Functional characterization of HMM II-C1 by actin-activated MgATPase activity demonstrated a Vmax of 0.55 + 0.18 s–1, which was half-maximally activated at an actin concentration of 16.5 + 7.2 μm. HMM II-C1 translocated actin filaments at a rate of 0.05 + 0.011 μm/s in the absence of tropomyosin and at 0.072 + 0.019 μm/s in the presence of tropomyosin in an in vitro motility assay. Myosins are protein molecular motors that bind to filamentous actin in an ATP-dependent manner. They are expressed as numerous classes in all eukaryotic cells (1.Sellers J.R. Myosins. Oxford University Press, Oxford, UK1999Google Scholar). Nonmuscle myosins include the ubiquitous conventional myosins (class II), which form filaments at relatively low ionic strength and share a number of biological properties with skeletal, cardiac and smooth muscle myosin (1.Sellers J.R. Myosins. Oxford University Press, Oxford, UK1999Google Scholar). They are expressed in both muscle and nonmuscle cells and are hexamers, consisting of a pair of heavy chains (200 kDa) and two pairs of light chains (20 and 17 kDa). Nonmuscle myosin II is one of the main motors interacting with cytoskeletal actin and is involved in regulating cytokinesis, cell motility, and cell polarity in many eukaryotic cells (1.Sellers J.R. Myosins. Oxford University Press, Oxford, UK1999Google Scholar, 2.Bresnick A.R. Curr. Opin. Cell Biol. 1999; 11: 26-33Crossref PubMed Scopus (316) Google Scholar). Two different nonmuscle myosin IIs have been described to date that are referred to as myosin II-A and II-B (3.Shohet R.V. Conti M.A. Kawamoto S. Preston Y.A. Brill D.A. Adelstein R.S. Proc. Natl. Acad. Sci. U. S. A. 1989; 86: 7726-7730Crossref PubMed Scopus (109) Google Scholar, 4.Katsuragawa Y. Yanagisawa M. Inoue A. Masaki T. Eur. J. Biochem. 1989; 184: 611-616Crossref PubMed Scopus (120) Google Scholar, 5.Simons M. Wang M. McBride O.W. Kawamoto S. Yamakawa K. Gdula D. Adelstein R.S. Weir L. Circ. Res. 1991; 69: 530-539Crossref PubMed Scopus (225) Google Scholar, 6.Kawamoto S. Adelstein R.S. J. Cell Biol. 1991; 112: 915-924Crossref PubMed Scopus (182) Google Scholar, 7.Phillips C.L. Yamakawa K. Adelstein R.S. J. Muscle Res. Cell Motil. 1995; 16: 379-389Crossref PubMed Scopus (108) Google Scholar, 8.Takahashi M. Kawamoto S. Adelstein R.S. J. Biol. Chem. 1992; 267: 17864-17871Abstract Full Text PDF PubMed Google Scholar, 9.Itoh K. Adelstein R.S. J. Biol. Chem. 1995; 270: 14533-14540Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar). These names are based on their unique heavy chain polypeptides, which are encoded by two different genes, located in humans on chromosomes 22 and 17 and in mice on chromosomes 15 and 11, respectively. It is presently not known whether nonmuscle myosin heavy chain (NMHC) 1The abbreviations used are: NMHC, nonmuscle myosin heavy chain; EST, expressed sequence tag; MOPS, 3-[N-morpholino]propanesulfonic acid; HMM II-C, noninserted heavy meromyosin, HMM II-C1, inserted heavy meromyosin; RT, reverse transcription; En, embryonic day n. II-A and II-B share the same or different light chain isoforms. There is one known form of NMHC II-A, whereas four alternatively spliced forms of NMHC II-B have been described (1.Sellers J.R. Myosins. Oxford University Press, Oxford, UK1999Google Scholar, 8.Takahashi M. Kawamoto S. Adelstein R.S. J. Biol. Chem. 1992; 267: 17864-17871Abstract Full Text PDF PubMed Google Scholar, 9.Itoh K. Adelstein R.S. J. Biol. Chem. 1995; 270: 14533-14540Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar). The localization of NMHCs II-A and II-B has been described for a number of different cultured cells and tissues (10.Maupin P. Phillips C.L. Adelstein R.S. Pollard T.D. J. Cell Sci. 1994; 107: 3077-3090Crossref PubMed Google Scholar, 11.Kelley C.A. Sellers J.R. Gard D.L. Bui D. Adelstein R.S. Baines I.C. J. Cell Biol. 1996; 134: 675-687Crossref PubMed Scopus (142) Google Scholar, 12.Kolega J. J. Cell Sci. 1998; 111: 2085-2095Crossref PubMed Google Scholar, 13.Takeda K. Yu Z.-X. Qian S. Chin T.K. Adelstein R.S. Ferrans V.J. Cell Motil. Cytoskeleton. 2000; 46: 59-68Crossref PubMed Scopus (64) Google Scholar, 14.Murakami N. Trenkner E. Elzinga M. Dev. Biol. 1993; 157: 19-27Crossref PubMed Scopus (38) Google Scholar), but no consistent pattern has emerged. Depending on the cell type, there appear to be areas that contain a particular myosin II isoform, but there are also areas where they clearly overlap at the light microscopic level. Some cells appear to express only one isoform, and a number of different approaches have been utilized to lower or remove one of the isoforms from both cultured cells (15.Wylie S.R. Wu P.J. Patel H. Chantler P.D. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 12967-12972Crossref PubMed Scopus (87) Google Scholar, 16.Wylie S.R. Chantler P.D. Nat. Cell Biol. 2001; 3: 88-92Crossref PubMed Scopus (80) Google and mice D. Ferrans V.J. Yu Z.-X. K. A. H. Preston Y.A. Adelstein R.S. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, D. Y. K. Kawamoto S. Yu Z.-X. Ferrans V.J. N. A. Preston Y.A. Adelstein R.S. J. 2000; PubMed Scopus Google Scholar, Conti M.A. Adelstein R.S. Y. J. 2001; PubMed Scopus Google Scholar). nonmuscle myosin II-A or II-B isoforms with a of have been These include the of nonmuscle myosin II-B with the of H. M. P. M. Cell Biol. PubMed Scopus Google and the of nonmuscle myosin II-A with the protein Adelstein R.S. PubMed Scopus Google Scholar), the M. M. M. A. J. J. PubMed Scopus Google Scholar), and the protein D.L. Sellers J.R. PubMed Scopus Google Scholar). of and data the of the of previously unrecognized myosin IIs Biol. 2001; PubMed Scopus Google Scholar). sequence have been as to nonmuscle myosin and a NMHC has been on human number Biol. 2001; PubMed Scopus Google Scholar). A. S. K. J. A. PubMed Scopus Google also found that this is and that this is in human and The of the to that the a NMHC, which we to as II-C, is a previously unrecognized to this protein from nonmuscle myosin to whether is expressed in different alternatively spliced and to properties as a myosin. of of and data used to for nonmuscle The for and of and was used to and and for the for to the of human and mouse and a previously unrecognized NMHC that we II-C. used to NMHC II-C the human sequence to nucleotides of on a at and to and and the mouse and as as different and in and of the human and that there are two alternatively spliced forms of NMHC II-C, the of which contains a of 24 nucleotides from an expression data from the and and was from mouse tissues was from the mRNA was in a of of and of II reverse in the by the in the presence of of and of was of the in the presence of of and of The used to the of NMHC II-C in human muscle and and used and from different human and mouse tissues. A from the of NMHC II-C from the was and used as a The was the and was in the at for The with at by two with at and to a and to The with probes to nucleotides of the noninserted NMHC II-C of from a of the pattern of tissue distribution the different NMHC in the The NMHC in was by the The data that the of the of the of the and was with different tissue and different of the of and mRNA NMHC was the The the inserted as and reverse from the tissues of mice was reverse and reverse The was by the The of at for and and at for for the four by at for and and at for for the to in the absence of reverse used as a for by The from was the for the which the presence of the inserted by on a and the presence of the inserted isoform in the was by an to the inserted sequence as a and of NMHC II-C The used for and for an 15 mouse mouse and human to in The of to with a filamentous protein in cultured used for The mouse sequence in by University of and affinity-purified by to NMHC II-A and II-B have been described previously C.L. Yamakawa K. Adelstein R.S. J. Muscle Res. Cell Motil. 1995; 16: 379-389Crossref PubMed Scopus (108) Google Scholar, P. Phillips C.L. Adelstein R.S. Pollard T.D. J. Cell Sci. 1994; 107: 3077-3090Crossref PubMed Google Scholar, 13.Takeda K. Yu Z.-X. Qian S. Chin T.K. Adelstein R.S. Ferrans V.J. Cell Motil. Cytoskeleton. 2000; 46: 59-68Crossref PubMed Scopus (64) Google Scholar). from mouse organs a of and and at The at for and the was In to the nonmuscle myosins by actin a of affinity-purified to the was used as described previously C.A. Sellers J.R. Gard D.L. Bui D. Adelstein R.S. Baines I.C. J. Cell Biol. 1996; 134: 675-687Crossref PubMed Scopus (142) Google Scholar). The and by on or and to the described at a concentration of for NMHC II-A, for II-B and for II-C. to nonmuscle actin and D. Y. K. Kawamoto S. Yu Z.-X. Ferrans V.J. N. A. Preston Y.A. Adelstein R.S. J. 2000; PubMed Scopus Google used to of of mouse heavy meromyosin II-C and HMM II-C1, both and the to a sequence the of the mouse NMHC II-C used or used as The with the The protein a protein Immunofluorescence of NMHC II isoforms in mouse was by The in and in at the and The in and at a of μm. the with and for at with NMHC II-A II-B and II-C at by with for at the a The a Baculovirus of HMM II-C and HMM of the of HMM II-C, by the sequence for the and an at the by a and a of the inserted isoform, we used a of nucleotides in the and the by The with the with the of the HMM II-C was and the was with a both light chains in cells Sellers J.R. Preston Y.A. Adelstein R.S. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). cells by of and the was with in and at and of HMM was as previously described L. Y. Sellers J.R. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google with the that was used in of The from the was a or used from the of and of in a of MOPS, and with was to the expressed or to as and the was for 15 at to the The was in A and and to the HMM from the actin Sellers J.R. Preston Y.A. Adelstein R.S. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). actin-activated MgATPase activity was at the in a in a and myosin light chain as previously described M. A. J. Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). In in vitro motility of the HMM was at as previously described A. Wang Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J.R. Wang E. Cell Biol. 1993; PubMed Scopus Google Scholar). The MOPS, and The on the as previously described A. Wang Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). and of NMHC on the of and sequence data in the different we the of the human and mouse NMHC II-C in two alternatively spliced We and the sequence of the mouse NMHC II-C and mRNA from mouse and was and at three to the of the The sequence of the mouse NMHC II-C is in number and for the alternatively spliced The protein sequence from this contains the of a myosin II heavy chain in and in M.A. Biochem. 1999; PubMed Scopus Google to The a of with the inserted exon and of the of NMHC II-C to of of both the of the of NMHC IIs and Biol. 2001; PubMed Scopus Google and M.A. Cell Motil. Cytoskeleton. 1993; PubMed Scopus Google Scholar), as as the heavy chain sequence that NMHC II-C constitutes a distinct branch of the nonmuscle/smooth muscle myosin heavy chain II The and NMHC II-A NMHC II-B and smooth muscle myosin heavy chain are than one of and NMHC II-C. the NMHC II-C is to this of myosin heavy chains than to myosin heavy chain the of of myosin isoform human and mouse and which is than the of the different isoforms the same the human smooth muscle and NMHC isoform is the noninserted isoform is the noninserted in a NMHC II-C mRNA of human tissue with a from the of human NMHC II-C or from the of the not showed the presence of a of with expression in The is also expressed in and is found in and is in with the of the tissue distribution of the human mRNA the of in which also showed that NMHC II-C is in muscle and is in and of a from the of human NMHC II-C to a human tissue with the in the and revealed the distribution of NMHC II-C and nonmuscle NMHC The that NMHC II-C mRNA is expressed in the which is for is by the tissue distribution which also of this in the which is with a of in II also that expression of NMHC II-C is low in organs of smooth as the and NMHCs II-A and II-B are relatively in tissues II and 7.Phillips C.L. Yamakawa K. Adelstein R.S. J. Muscle Res. Cell Motil. 1995; 16: 379-389Crossref PubMed Scopus (108) Google Scholar), whereas the mRNA NMHC II-C is II in human fetal tissue contains or no NMHC II-C mRNA with adult tissues the for fetal tissue in the with found for adult was with two different of NMHC II-A, II-B, and II-C mRNA in human the tissue in a We used to the of the inserted and noninserted mRNA for the 24 nucleotides in loop of the the distribution of the inserted and noninserted mRNA in a of mouse tissues. The that the inserted mRNA is the one in adult mouse and and contain of both and muscle and contain low of the inserted is a NMHC II-C is not expressed in this of the inserted sequence mice and humans showed a in one for mice and for NMHC II-C by of the to the mouse sequence is demonstrated in an of a myosin all three nonmuscle myosin II isoforms by actin from mouse and and Sellers J.R. Preston Y.A. Adelstein R.S. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). NMHC II-C is the to the II-C as by the with to II-A, II-B, and II-C and The absence of NMHC II-A and II-B from the also that NMHC II-C is a with to the myosin heavy chains than a of II-C with II-A or II-B. is an the protein expression of NMHC II-A, II-B, and II-C. that two are for one tissue and one with of as by and of nonmuscle actin and by used to protein not The that NMHC II-C from II-A in low or in and The presence of NMHC II-C in and and absence in expression pattern from that of II-B. The to the human NMHC II-C sequence was used for this the to the mouse sequence in the of the microscopy was used to the distribution of NMHC II-C, II-B, and II-A in mouse at and and the widespread distribution of all three isoforms in the mouse concentration of II-A and II-C in the at is to to the presence of and of are of the mouse from the as the for II-C in the at for II-B at the and of the and for II-A in the and of in the localization of the isoforms in the for II-C in the of the whereas II-B is expressed in the cells and the cells the for II-A is in the clearly the isoform is also in both the and cells and of that II-C is in the of the cells in the mouse for II-A is also relatively in is not to the of the as is II-C that II-B in the cells the but not in the of HMM II-C and HMM used the Baculovirus expression to both alternatively spliced forms of heavy meromyosin II-C with the and myosin light HMM II-C and the inserted isoform HMM II-C1 to muscle actin and from in the presence of for HMM II-C in The a HMM II-C and HMM II-C1 In this the HMM II-C1 was used for characterization the in was to actin to The that both HMM II-C and II-C1 of to actin in the absence of and in the presence of that both isoforms share a biological of However, we only to quantities of the inserted isoform, HMM II-C1, for characterization of the actin-activated MgATPase activity and in vitro motility assay. These are in and are with previously for NMHC II-B and II-A The that HMM II-C1 has a Vmax that of II-B and II-A and actin filaments at the same rate as HMM II-B, than HMM of MgATPase and in vitro motility and inserted 0.011 0.019 Sellers J.R. Preston Y.A. Adelstein R.S. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Sellers J.R. Preston Y.A. Adelstein R.S. J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google and inserted Conti M.A. D. Sellers J.R. 2000; PubMed Scopus Google and inserted in a In this we for a previously unrecognized myosin II that is expressed at the protein level in both muscle and nonmuscle tissues. We to the myosin heavy chain as NMHC II-C. We the nucleotide and sequence of two alternatively spliced forms of NMHC II-C, which contains all the of conventional myosin heavy Using antibodies, we that this sequence is expressed as a A. S. K. J. A. PubMed Scopus Google have the of the human and have the and mRNA distribution of NMHC II-C, as by an data the spliced NMHC II-C1 described but the of spliced forms of this myosin of the In we found data but not by distribution that NMHC II-C is than the by A. S. K. J. A. PubMed Scopus Google Scholar). a of the of two different approaches to the level of expression of NMHC II-C the of an and the of the level of to the number of in a expression patterns the is from different for many genes, that are not and In both we found that NMHC II-C is expressed in human muscle and in and the of the expression level in the the of the expression in both approaches is the are the in data the expression is and we that one patterns of expression from data bases. We the patterns of expression of NMHCs in human tissues at the level tissue and a to patterns of expression of the different NMHCs probes of different in the of the of be However, the tissue distribution of mRNA the or as a for different in a manner. is that the data in II for NMHC II-A and II-B are in with that previously based on (3.Shohet R.V. Conti M.A. Kawamoto S. Preston Y.A. Brill D.A. Adelstein R.S. Proc. Natl. Acad. Sci. U. S. A. 1989; 86: 7726-7730Crossref PubMed Scopus (109) Google Scholar, 4.Katsuragawa Y. Yanagisawa M. Inoue A. Masaki T. Eur. J. Biochem. 1989; 184: 611-616Crossref PubMed Scopus (120) Google Scholar, 5.Simons M. Wang M. McBride O.W. Kawamoto S. Yamakawa K. Gdula D. Adelstein R.S. Weir L. Circ. Res. 1991; 69: 530-539Crossref PubMed Scopus (225) Google Scholar, 6.Kawamoto S. Adelstein R.S. J. Cell Biol. 1991; 112: 915-924Crossref PubMed Scopus (182) Google Scholar, 7.Phillips C.L. Yamakawa K. Adelstein R.S. J. Muscle Res. Cell Motil. 1995; 16: 379-389Crossref PubMed Scopus (108) Google Scholar). The tissue distribution of NMHC II-C is qualitatively different from myosin II heavy chains in and that has a different from cytoskeletal NMHC II-C is in human adult tissues than in human fetal tissues. NMHC II-A and II-B, is not expressed in mouse embryonic A. E. Adelstein R.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google found that the of the expression of NMHC II-C, which the that myosin II-C is in tissues. In NMHC II-C is in human areas and that are in cells and with cell the the of NMHC II-C are low in organs with smooth as and from nonmuscle myosin Nonmuscle myosin II-C from NMHC II-A and II-B as by low expression in and the in is an protein E. Adelstein R.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). myosins that are known to be are cardiac Two cardiac myosin heavy chains have been described in the and heavy is by as and and Circ. Res. PubMed Scopus Google Scholar, P. Circ. Res. 1995; PubMed Scopus Google Scholar, A. J. Circ. Res. 1991; PubMed Scopus Google Scholar). in cardiac are with isoform by in the and by the Circ. Res. PubMed Scopus Google Scholar). is consistent with the different and properties of the two isoforms (1.Sellers J.R. Myosins. Oxford University Press, Oxford, UK1999Google Scholar, M. S. H. S. T. Circ. Res. 1993; PubMed Scopus Google Scholar, E. Sellers J.R. J. Full Text PDF PubMed Scopus Google Scholar). The for NMHC II-A and NMHC II-B are different and that two myosins not have M. A. J. Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, M. Wang A. Y. Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). NMHC II-A as a but conventional myosin with a low that of from actin M. Wang A. Y. Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). In NMHC II-B has a that of conventional and myosins as myosin M. A. J. Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). that NMHC II-B be for in a manner. The for NMHC II-C to be both the in vitro motility and the actin-activated MgATPase activity of HMM II-C1 on of the myosin light chain. there was a in the of the expression of the two alternatively spliced forms of HMM II-C. we the inserted form by in the to a of the noninserted form and the sequence the form protein which a biochemical The of of nucleotide sequence on expression level has been A. Wang Sellers J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). cardiac which form both as and and as Circ. Res. PubMed Scopus Google Scholar), nonmuscle myosins form only C.A. Sellers J.R. Gard D.L. Bui D. Adelstein R.S. Baines I.C. J. Cell Biol. 1996; 134: 675-687Crossref PubMed Scopus (142) Google Scholar). is for NMHC II-C of NMHC II-C, no NMHC II-A or II-B was found in the The was used to the ubiquitous forms of myosin II and the isoforms. However, this is myosins are not only expressed in all of nonmuscle tissue but also have a significant in the and of muscle tissues as the and smooth K. Yu Z.-X. Qian S. Chin T.K. Adelstein R.S. Ferrans V.J. Cell Motil. Cytoskeleton. 2000; 46: 59-68Crossref PubMed Scopus (64) Google Scholar, D. Ferrans V.J. Yu Z.-X. K. A. H. Preston Y.A. Adelstein R.S. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, M. H. M. Nat. Cell Biol. 2000; PubMed Scopus Google Scholar, A. Dev. Biol. PubMed Scopus Google Scholar). and J.R. J. Cell Biol. PubMed Scopus Google described this in myosin as as and the However, this the that of myosins also to the and not myosins from myosins are to be involved in cell and polarity and with cytoskeletal we the of the cytoskeletal myosin no at is a is we to the Using to all three nonmuscle we the distribution of the isoforms at and in mice particular at is the of NMHC II-C in mouse the of NMHC II-B in the at the and areas and the of NMHC II-A in the of the and of the and cells of the also showed in the distribution of the three isoforms but clearly cells where the distribution also and and cells are of one cells contain NMHC II-A and K. Adelstein R.S. J. Cell Sci. 1995; PubMed Google Scholar). the presence of both NMHC II-A and II-C in cells not for the of II-B of this isoform D. Ferrans V.J. Yu Z.-X. K. A. H. Preston Y.A. Adelstein R.S. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, Conti M.A. Adelstein R.S. Y. J. 2001; PubMed Scopus Google or NMHC II-B to than of the D. Y. K. Kawamoto S. Yu Z.-X. Ferrans V.J. N. A. Preston Y.A. Adelstein R.S. J. 2000; PubMed Scopus Google Scholar). of in NMHC II-A in and in humans A. A. J. A. J. 2001; 69: Full Text Full Text PDF PubMed Scopus Google and is not for by the presence of NMHC II-B and II-C in the same tissues or the same a in mouse NMHC II-B in in as as cardiac and by the myosin II isoforms. It be of to the of in NMHC II-C in both humans and We for with antibodies, Wang and for in the and and for We also for