Cloning of the cDNA encoding rat myosin heavy chain-A and evidence for the absence of myosin heavy chain-B in cultured rat mast (RBL-2H3) cells.
The complete amino acid sequence (1961 amino acids) of a vertebrate cellular myosin heavy chain-A was deduced from cDNA clones of a secretory rat mast cell line, the RBL-2H3 cell. The rat, human and chicken cellular myosin heavy chain-A exhibited high similarity in domains that allow binding of ATP and actin. The amino acid sequence of non-muscle myosin heavy chain-A from rat was 96% identical to that in human and 92% identical to that in chicken. Northern blot analysis of mRNA indicated the presence of single message of 7.4 kilobases. Northern blot, reverse-transcriptase polymerase chain reaction, and Western blot with isoform-specific antibodies indicated that RBL-2H3 cells expressed exclusively myosin heavy chain-A. Unlike rat PC12 cells, as well as a wide variety of other cultured cells and tissues, myosin heavy chain-B mRNA and protein were not detectable in RBL-2H3 cells. Because RBL-2H3 cells can be stimulated to release secretory granules as well as newly generated arachidonic acid and cytokines but lack myosin heavy chain-B, this cell line may provide a unique model to study the role of myosin heavy chain-A in cellular responses to antigen and other stimulants.
Choi
O H
OH
Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1760, USA.
Park
C S
CS
Itoh
K
K
Adelstein
R S
RS
Beaven
M A
MA
D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002645:Chickens; D003001:Cloning, Molecular; D017931:DNA Primers; D006801:Humans; D008407:Mast Cells; D020409:Molecular Motor Proteins; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D024501:Nonmuscle Myosin Type IIB; D016716:PC12 Cells; D016133:Polymerase Chain Reaction; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D000199:Actins; D017931:DNA Primers; C103814:MYH9 protein, human; D020409:Molecular Motor Proteins; C491238:Myh9 protein, rat; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D024501:Nonmuscle Myosin Type IIB; C103815:nonmuscle myosin type IIB heavy chain; D018995:Myosin Heavy Chains