Disease relevance of myoJ

• Recent studies have revealed that familial hypertrophic cardiomyopathy (FHC) is caused by missence mutations in myosin heavy chain or other sarcomeric proteins [1].
• Coexpression and assembly of myosin heavy chain and myosin light chain in Escherichia coli [2].
• A cDNA clone, SMHC-29, encoding the light meromyosin of smooth muscle myosin heavy chain (MHC), was isolated from a rabbit uterus cDNA library constructed in phage lambda gt11 [3].

Psychiatry related information on myoJ

• Myosin-IE motor activity is regulated by myosin heavy chain phosphorylation, which increases the coupling efficiency between the actin and nucleotide binding sites tenfold and the motile activity more than fivefold [4].

High impact information on myoJ

• Antisense RNA inactivation of myosin heavy chain gene expression in Dictyostelium discoideum [5].
• A plasmid carrying a G418 resistance gene and the amino terminal half of the myosin heavy chain gene was used to transfect Dictyostelium [6].
• The eukaryotic slime mold Dictyostelium discoideum has a single conventional myosin heavy chain gene (mhcA) [7].
• A fragment of the Dictyostelium discoideum myosin heavy chain gene representing heavy meromyosin was coexpressed in Escherichia coli with the entire essential myosin light chain from the scallop [2].
• Furthermore, S1 nuclease mapping has revealed that this smooth muscle MHC gene for SMHC-29 is specifically expressed in smooth muscles of vascular and nonvascular types but not in the striated muscles or nonmuscle cells [3].

Biological context of myoJ

• The myoJ gene encodes a high molecular weight myosin, and analysis of the available deduced amino acid sequence reveals that it possesses six IQ motifs and sequences typical of alpha helical coiled coils in the tail region [8].
• The 7.8 kb myoJ mRNA is expressed all throughout the life cycle of D. discoideum [8].
• By coexpressing different myosin heavy chain and myosin light chain combinations, it should be possible to study various isoforms of these two proteins, which are both products of multigene families in mammals [2].
• Conserved protein domains in a myosin heavy chain gene from Dictyostelium discoideum [9].
• The 2116-amino acid myosin heavy chain sequence from Dictyostelium discoideum was determined from DNA sequence analysis of the cloned gene [9].

Anatomical context of myoJ

• Characterization of a mammalian smooth muscle myosin heavy chain cDNA clone and its expression in various smooth muscle types [3].
• We have studied three proteins that change their association with the cytoskeleton after stimulation of amoebae with the chemoattractant cyclic AMP: (1) actin, (2) a protein with an apparent Mr of 190 x 10(3) and (3) myosin heavy chain [10].
• Two different Dictyostelium discoideum cell lines that lack myosin heavy chain protein (MHC A) have been previously described [11].
• In order to assess the functional relationship between sarcomeric and cytoplasmic myosins, a chimeric gene encoding the Dd myosin head and subfragment 2 fused to rat beta cardiac LMM was transfected into both wild-type and Dd mhc null cells [12].
• It is concluded that an intact myosin heavy chain gene is required to maintain the cell type specific budding pattern and the correct localization and deposition of chitin and cell wall components during cell growth and division [13].

Associations of myoJ with chemical compounds

• The expressed myosin heavy chain and essential myosin light chain copurify through ammonium sulfate fractionation, anion exchange, and gel filtration chromatography [2].
• The myosin heavy chain kinase is specific to Dictyostelium myosin heavy chain, and the phosphorylated amino acid is threonine [14].
• In XP55 myosin heavy chain showed an initial drop after cyclic AMP stimulation, with a trough at 3-10 s followed by a rapid rise to a sharp peak at 20-25 s [10].
• For the genes we have tested in these studies (myosin heavy chain kinases B and C), the efficiency of the double gene targeting event is found in the range of 2%-5% of all blasticidin-resistant colonies following the transfection step [15].

Regulatory relationships of myoJ

• The mhcA cells have negligible amounts of MHC A protein while the HMM cells express normal amounts of a fragment of the myosin heavy chain protein similar to heavy meromyosin (HMM) [11].

Other interactions of myoJ

• 3. By the addition of calmodulin, the inhibition of myosin heavy-chain phosphorylation was further enhanced [16].

Analytical, diagnostic and therapeutic context of myoJ

• To investigate the functional impact of FHC mutations in myosin heavy chain, mutants of Dictyostelium discoideum myosin II equivalent to human FHC mutations were generated by site-directed mutagenesis, and their motor function was characterized at the molecular level [1].
• The myosin heavy chain gene A, mhcA, from E. histolytica was identified by polymerase chain reaction [17].

References