title: Non-muscle myosin heavy chain IIA and IIB interact and co-localize in living cells: relevance for MYH9-related disease.
abstract: Myosins of class II constitute part of a superfamily of several classes of proteins expressed in almost all eukaryotic cell types. Differences in the heavy chains produce three isoforms of class II non-muscle myosins (A, B and C), which are widely distributed in most tissues and thought to be components of the cell motor systems, although specific functional roles are largely unknown. In particular, it is still a matter of debate whether they interact and have overlapping or distinct functions. This argument is relevant not only to cell physiology, but also to human pathology since mutations of the MYH9 gene encoding non-muscle myosin heavy chain II A (NMMHC-A) cause MYH9-related disease (MYH9-RD), an autosomal dominant disorder characterized by platelet macrocytosis, thrombocytopenia and leukocyte inclusions, variably associated with sensorineural hearing loss, cataracts and/or glomerulonephritis. In this study, we report the results of yeast two-hybrid screening showing that the C-terminals of NMMHC-A and -B interact. This interaction was confirmed by immunoprecipitation in transfected COS-7 cells and in skin fibroblasts naturally expressing both isoforms. Moreover, our immunomorphological study revealed that isoforms A and B co-localize in fibroblasts, erythroblasts and kidney cells. These results suggest that isoforms A and B are strictly related molecules and support the hypothesis that their interrelationship could be involved both in the variability of clinical phenotype and selectivity of tissue damage of MYH9-RD.
authors.affiliation: Laboratory of Molecular Genetics, G. Gaslini Institute, 16147 Genova, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Marini
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bruschi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pecci
authors.forename: Roberta
authors.initials: R
authors.lastname: Romagnoli
authors.forename: Luca
authors.initials: L
authors.lastname: Musante
authors.forename: Giovanni
authors.initials: G
authors.lastname: Candiano
authors.forename: Gian Marco
authors.initials: GM
authors.lastname: Ghiggeri
authors.forename: Carlo
authors.initials: C
authors.lastname: Balduini
authors.forename: Marco
authors.initials: M
authors.lastname: Seri
authors.forename: Roberto
authors.initials: R
authors.lastname: Ravazzolo
mesh_terms: D000818:Animals; D001791:Blood Platelet Disorders / Q000235:genetics / Q000473:pathology; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000737:chemistry; D019556:COS Cells; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007668:Kidney / Q000737:chemistry / Q000166:cytology; D018613:Microscopy, Confocal; D020409:Molecular Motor Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D018995:Myosin Heavy Chains / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D024507:Nonmuscle Myosin Type IIA / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D024501:Nonmuscle Myosin Type IIB / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D050199:Podocytes / Q000166:cytology; D011485:Protein Binding; D013921:Thrombocytopenia / Q000235:genetics / Q000473:pathology; D020798:Two-Hybrid System Techniques
chemical_list: C103814:MYH9 protein, human; D020409:Molecular Motor Proteins; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB; D018995:Myosin Heavy Chains