SPEG
Function
Isoform 3 may have a role in regulating the growth and differentiation of arterial smooth muscle cells.
Involvement in disease
Myopathy, centronuclear, 5
CNM5
A form of centronuclear myopathy, a congenital muscle disorder characterized by progressive muscular weakness and wasting involving mainly limb girdle, trunk, and neck muscles. It may also affect distal muscles. Weakness may be present during childhood or adolescence or may not become evident until the third decade of life. Ptosis is a frequent clinical feature. The most prominent histopathologic features include high frequency of centrally located nuclei in muscle fibers not secondary to regeneration, radial arrangement of sarcoplasmic strands around the central nuclei, and predominance and hypotrophy of type 1 fibers. CNM5 features include severe neonatal hypotonia with respiratory insufficiency, difficulty feeding, and delayed motor development. Some patients die in infancy, and some develop dilated cardiomyopathy.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
May be autophosphorylated.
Sequence Similarities
Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.
Tissue Specificity
Isoform 1 is preferentially expressed in striated muscle. Non-kinase form such as isoform 3 is predominantly expressed in the aorta. Isoform 3 appears to be expressed only in highly differentiated ASMC in normal vessel walls and down-regulated in dedifferentiated ASMC in vivo. In response to vascular injuries ASMC dedifferentiate and change from a quiescent and contractile phenotype to a proliferative and synthetic phenotype. This proliferation of vascular smooth muscle cells is one of the most prominent features of atherosclerosis.
Cellular localization
- Isoform 3
- Nucleus
Alternative names
APEG1, KIAA1297, SPEG, Striated muscle preferentially expressed protein kinase, Aortic preferentially expressed protein 1, APEG-1