Bifunctional enzyme that possesses both UDP-N-acetylglucosamine 2-epimerase and N-acetylmannosamine kinase activities, and serves as the initiator of the biosynthetic pathway leading to the production of N-acetylneuraminic acid (NeuAc), a critical precursor in the synthesis of sialic acids. By catalyzing this pivotal and rate-limiting step in sialic acid biosynthesis, this enzyme assumes a pivotal role in governing the regulation of cell surface sialylation, playing a role in embryonic angiogene

Cytoplasm, cytosol

Sialuria

In sialuria, free sialic acid accumulates in the cytoplasm and gram quantities of neuraminic acid are secreted in the urine. The metabolic defect involves lack of feedback inhibition of UDP-GlcNAc 2-epimerase by CMP-Neu5Ac, resulting in constitutive overproduction of free Neu5Ac. Clinical features include variable degrees of developmental delay, coarse facial features and hepatomegaly. Sialuria inheritance is autosomal dominant.

Plays an important role in cell protection against oxidative stress and in the regulation of redox-related calcium homeostasis. Regulates the calcium level of the ER by protecting the calcium pump ATP2A2 against the oxidoreductase ERO1A-mediated oxidative damage. Within the ER, ERO1A activity increases the concentration of H(2)O(2), which attacks the luminal thiols in ATP2A2 and thus leads to cysteinyl sulfenic acid formation (-SOH) and SEPN1 reduces the SOH back to free thiol (-SH), thus restor

Endoplasmic reticulum membrane

Congenital myopathy 3 with rigid spine

An autosomal recessive, slowly progressive muscular disorder apparent from birth or early childhood and characterized by hypotonia, proximal muscle weakness, poor axial muscle strength, scoliosis and neck weakness, and a variable degree of spinal rigidity. Most patients remain ambulatory. Early ventilatory insufficiency may lead to death by respiratory failure. Additional features may include facial muscle weakness, amyotrophy, joint contractures, distal hyperlaxity, pulmonary hypertension with secondary cardiac dysfunction, and insulin resistance in patients with a low BMI. Skeletal muscle biopsy typically shows multiminicores and other abnormal non-specific myopathic findings.

Myosins are actin-based motor molecules with ATPase activity essential for muscle contraction

Cytoplasm, myofibril

Congenital myopathy 6 with ophthalmoplegia

A muscular disorder characterized by mild-to-moderate muscle weakness, ophthalmoplegia, and contractures at birth in some patients. Muscle biopsies from patients show predominance of type 1 fibers and small or absent type 2A fibers. The disease is non-progressive or it progresses very slowly. Inheritance is autosomal dominant or recessive.

Required for the assembly of the V0 complex of the vacuolar ATPase (V-ATPase) in the endoplasmic reticulum

Endoplasmic reticulum membraneEndoplasmic reticulum-Golgi intermediate compartment membraneCytoplasmic vesicle, COPII-coated vesicle membrane

Myopathy, X-linked, with excessive autophagy

A muscle disorder characterized by childhood early onset of a slowly progressive proximal limb muscle weakness (especially in legs) and elevation of serum creatine kinase, without evidence of cardiac, respiratory or central nervous system involvement. Histopathological analysis reveals diseased muscle fibers that are not necrotic, but show abnormal autophagic vacuolation as a manifestation of excessive autophagic activity in skeletal muscle cells.

Necessary for the fragmentation of Golgi stacks during mitosis and for their reassembly after mitosis. Involved in the formation of the transitional endoplasmic reticulum (tER). The transfer of membranes from the endoplasmic reticulum to the Golgi apparatus occurs via 50-70 nm transition vesicles which derive from part-rough, part-smooth transitional elements of the endoplasmic reticulum (tER). Vesicle budding from the tER is an ATP-dependent process. The ternary complex containing UFD1, VCP and

Cytoplasm, cytosolEndoplasmic reticulumNucleusCytoplasm, Stress granule

Inclusion body myopathy with early-onset Paget disease with or without frontotemporal dementia 1

An autosomal dominant disease characterized by disabling muscle weakness clinically resembling to limb girdle muscular dystrophy, osteolytic bone lesions consistent with Paget disease, and premature frontotemporal dementia. Clinical features show incomplete penetrance.

Heterogeneous nuclear ribonucleoprotein (hnRNP) that associates with nascent pre-mRNAs, packaging them into hnRNP particles. The hnRNP particle arrangement on nascent hnRNA is non-random and sequence-dependent and serves to condense and stabilize the transcripts and minimize tangling and knotting. Packaging plays a role in various processes such as transcription, pre-mRNA processing, RNA nuclear export, subcellular location, mRNA translation and stability of mature mRNAs (PubMed:19099192). Forms

NucleusNucleus, nucleoplasmCytoplasmCytoplasmic granuleSecreted, extracellular exosome

Inclusion body myopathy with early-onset Paget disease with or without frontotemporal dementia 2

An autosomal dominant disease characterized by disabling muscle weakness clinically resembling to limb girdle muscular dystrophy, osteolytic bone lesions consistent with Paget disease, and premature frontotemporal dementia. Clinical features show incomplete penetrance.

Involved in the packaging of pre-mRNA into hnRNP particles, transport of poly(A) mRNA from the nucleus to the cytoplasm and modulation of splice site selection (PubMed:17371836). Plays a role in the splicing of pyruvate kinase PKM by binding repressively to sequences flanking PKM exon 9, inhibiting exon 9 inclusion and resulting in exon 10 inclusion and production of the PKM M2 isoform (PubMed:20010808). Binds to the IRES and thereby inhibits the translation of the apoptosis protease activating

NucleusCytoplasm

Inclusion body myopathy with early-onset Paget disease with or without frontotemporal dementia 3

An autosomal dominant disease characterized by disabling muscle weakness clinically resembling to limb girdle muscular dystrophy, osteolytic bone lesions consistent with Paget disease, and premature frontotemporal dementia. Clinical features show incomplete penetrance.

Key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The size and extensibility of the cross-links are the main determinants of sarcomere extensibility properties of muscle. In non-muscle cells, seems to play a role in chromosome condensation and chromosome segregation during mitosis. Might link the lamina network to ch

CytoplasmNucleus

Myopathy, myofibrillar, 9, with early respiratory failure

An autosomal dominant myopathy characterized by adulthood onset of weakness in proximal, distal, axial and respiratory muscles. Pelvic girdle weakness, foot drop and neck weakness are the main symptoms at onset, but ultimately the weakness usually involves the proximal compartment of both upper and lower limbs. Additional features include variable degrees of Achilles tendon contractures, spinal rigidity and muscle hypertrophy. Respiratory involvement often leads to requirement for non-invasive ventilation support.

Binds specifically to calcyclin in a calcium-dependent manner (By similarity). Required for midbody formation and completion of the terminal phase of cytokinesis

CytoplasmMelanosomeNucleus envelopeNucleus, nucleoplasmCytoplasm, cytoskeleton, spindle

Amyotrophic lateral sclerosis 23

A form of amyotrophic lateral sclerosis, a neurodegenerative disorder affecting upper motor neurons in the brain and lower motor neurons in the brain stem and spinal cord, resulting in fatal paralysis. Sensory abnormalities are absent. The pathologic hallmarks of the disease include pallor of the corticospinal tract due to loss of motor neurons, presence of ubiquitin-positive inclusions within surviving motor neurons, and deposition of pathologic aggregates. The etiology of amyotrophic lateral sclerosis is likely to be multifactorial, involving both genetic and environmental factors. The disease is inherited in 5-10% of the cases. ALS23 is an autosomal dominant form with incomplete penetrance.