Tropomyosin-2 (TPM2) Human Recombinant Protein

This gene encodes beta-tropomyosin, a member of the actin filament binding protein family, and mainly expressed in slow, type 1 muscle fibers. Mutations in this gene can alter the expression of other sarcomeric tropomyosin proteins, and cause cap disease, nemaline myopathy and distal arthrogryposis syndromes. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Mar 2009]

TPM2: Binds to actin filaments in muscle and non-muscle cells. Plays a central role, in association with the troponin complex, in the calcium dependent regulation of vertebrate striated muscle contraction. Smooth muscle contraction is regulated by interaction with caldesmon. In non-muscle cells is implicated in stabilizing cytoskeleton actin filaments. The non-muscle isoform may have a role in agonist-mediated receptor internalization. Defects in TPM2 are the cause of nemaline myopathy type 4 (NEM4). A form of nemaline myopathy. Nemaline myopathies are muscular disorders characterized by muscle weakness of varying severity and onset, and abnormal thread-or rod-like structures in muscle fibers on histologic examination. Nemaline myopathy type 4 presents from infancy to childhood with hypotonia and moderate-to-severe proximal weakness with minimal or no progression. Major motor milestones are delayed but independent ambulation is usually achieved, although a wheelchair may be needed in later life. Defects in TPM2 are the cause of distal arthrogryposis type 1A (DA1A). A form of distal arthrogryposis, a disease characterized by congenital joint flexures or contractures that mainly involve the distal parts of the limbs, and affect two or more different body areas in the absence of a primary neurological or muscle disease. Distal arthrogryposis type 1 is characterized largely by camptodactyly and clubfoot. Hypoplasia and/or absence of some interphalangeal creases is common. The shoulders and hips are less frequently affected. Belongs to the tropomyosin family. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Motility/polarity/chemotaxis; Motor

Chromosomal Location of Human Ortholog: 9p13

Cellular Component: muscle thin filament tropomyosin; cytosol

Molecular Function: structural constituent of muscle; actin binding

Biological Process: regulation of ATPase activity; muscle contraction; muscle filament sliding

Disease: Nemaline Myopathy 4; Arthrogryposis, Distal, Type 1a; Myopathy, Congenital, With Fiber-type Disproportion; Arthrogryposis, Distal, Type 2b