myosin heavy chain 9; myosin-9; myosin heavy chain, non-muscle IIa; non-muscle myosin heavy chain IIa; NMMHC II-a; NMMHC-IIA; cellular myosin heavy chain, type A; non-muscle myosin heavy chain A; NMMHC-A (MYH9)

Function

• myosin heavy chain
• role in cytokinesis, cell shape, & specialized functions such as secretion & capping
• interacts with PDLIM2 (putative)

Structure

• myosin is a hexameric protein that consists of
  • 2 myosin heavy chain subunits
  • 2 myosin essential light chain subunits
  • 2 myosin regulatory light chain subunits
• each myosin heavy chain can be split into 1 light meromyosin & 1 heavy meromyosin; it can later be split further into 2 globular subfragments (S1) & 1 rod-shaped subfragment (S2)
• rodlike tail sequence is highly repetitive, showing cycles of a 28-residue repeat pattern composed of 4 heptapeptides, characteristic for alpha-helical coiled coils
• contains 1 IQ domain
• contains 1 myosin head-like domain

Alternative splicing

named isoforms=2

Expression

• found in non muscle tissue
• in the kidney, expressed in the renal glomeruli
• expressed in leukocytes

Pathology

• defects in MYH9 are the cause of:
  • May-Hegglin anomaly
  • Sebastian syndrome
  • Fechtner syndrome
  • Alport syndrome with macrothrombocytopenia
  • Epstein syndrome
  • non-syndromic sensorineural deafness, autosomal dominant type 17
  • macrothrombocytopenia with sensorineural deafness
• subjects with mutations in the motor domain of MYH9 present with severe thrombocytopenia & develop nephritis & deafness before the age of 40 years, while those with mutations in the tail domain have a much lower risk of noncongenital complications & significantly higher platelet counts
• mutations at residue 1933 do not induce kidney damage or cataracts & cause deafness only in the elderly
• mutations in position 702 result in severe thrombocytopenia & produce nephritis & deafness at a juvenile age
• alterations at residue 1424 or 1841 result in intermediate clinical pictures

More general terms

• myosin heavy chain

Additional terms

• myosin

Database

• UniProt: http://www.uniprot.org/uniprot/P35579.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=4627
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:4627
• OMIM: https://mirror.omim.org/entry/153640
• OMIM: https://mirror.omim.org/entry/153650
• OMIM: https://mirror.omim.org/entry/155100
• OMIM: https://mirror.omim.org/entry/160775
• OMIM: https://mirror.omim.org/entry/600208
• OMIM: https://mirror.omim.org/entry/603622
• OMIM: https://mirror.omim.org/entry/605249