atrophy

Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Probably recognizes and binds to phosphorylated target proteins during skeletal muscle atrophy. Recognizes TERF1.

Vesicle-associated membrane protein-associated protein B C, also known as VAMP-B VAMP-C, VAMP-associated protein B C, VAP-B VAP-C and VAPB, is a single-pass type IV membrane protein that belongs to the VAMP-associated protein (VAP) family. VAPB contains one MSP domain. VAPB may play a role in vesicle trafficking. VAPB forms a heterodimer with VAPA. VAPB interacts with VAMP1 and VAMP2. Defects in VAPB are the cause of amyotrophic lateral sclerosis type 8 ( ALS8 ) which is a familial form of amyotrophic lateral sclerosis, a neurodegenerative disorder affecting upper and lower motor neurons and resulting in fatal paralysis. Defects in VAPB are also a cause of spinal muscular atrophy autosomal dominant Finkel type (SMAF) which is characterized by proximal muscle weakness that begins in the lower limbs and then progresses to upper limbs.

Cyclin-dependent kinase inhibitor 2D(also known as CDKN2D or p19ink4d), a member of the INK4 family of cyclin-dependent kinase (CDK) inhibitors, negatively regulates the cyclin D-CDK4 6 complexes, which promote G1 S transition by phosphorylating the retinoblastoma tumor-suppressor gene product. It is clearly shown that DNA repair is the main target of p19ink4d effect and that diminished apoptosis is a downstream event. Experiments has uncovered a role of p19INK4d as a regulator of DNA-damage-induced apoptosis and suggest that it protects cells from undergoing apoptosis by allowing a more efficient DNA repair. It has been demonstrated that p19INK4d expression enhances cell survival under genotoxic conditions. Previous work has shown that inactivation of the cyclin-dependent kinase inhibitor (CKI) p19(Ink4d) leads to progressive hearing loss attributable to inappropriate DNA replication and subsequent apoptosis of hair cells. It may also involved in male reproductive function including testicular atrophy, alteration in serum follicle stimulating hormone, qualitative increase in germ cell apoptosis, and delayed kinetics of meiotic prophase markers.

E3 ubiquitin ligase. Mediates the ubiquitination and subsequent proteasomal degradation of CKM, GMEB1 and HIBADH. Regulates the proteasomal degradation of muscle proteins under amino acid starvation, where muscle protein is catabolized to provide other organs with amino acids. Inhibits de novo skeletal muscle protein synthesis under amino acid starvation. Regulates proteasomal degradation of cardiac troponin I TNNI3 and probably of other sarcomeric-associated proteins. May play a role in striated muscle atrophy and hypertrophy by regulating an anti-hypertrophic PKC-mediated signaling pathway. May regulate the organization of myofibrils through TTN in muscle cells.

Protein-arginine deiminase type-4, also known as HL-6 PAD, Peptidylarginine deiminase IV, Protein-arginine deiminase type I V and PADI4, is a cytoplasm and nucleus protein that belongs to the protein arginine deiminase family. PADI4 is expressed in CD34+stem cells in normal tissues, and many more CD34+ cells expressing PADI4 are present in tumour tissues. PADI4 post-translationally converts peptidylarginine to citrulline, a process called citrullination. Studies have demonstrated the high expression of PADI4 in various malignant tumor tissues. PADI4 is also expressed at high levels in the blood of patients with some malignant tumors. Citrullination of histone, cytokeratin, antithrombin and fibronectin have been confirmed to be involved in abnormal apoptosis, high coagulation, and disordered cell proliferation and differentiation, all of which are main features of malignant tumors. PADI4 may play an important role in tumorigenesis. Genetic variations in PADI4 are a cause of susceptibility to rheumatoid arthritis (RA). It is a systemic inflammatory disease with autoimmune features and a complex genetic component. It primarily affects the joints and is characterized by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures.

v-akt murine thymoma viral oncogene homolog 1 (AKT1), or protein kinase B-alpha (PKB-ALPHA) is a serine-threonine protein kinase, belonging to the Protein Kinase Superfamily. AKT1 is a major mediator of the responses to insulin, insulin-like growth factor 1 (IGF1), and glucose. AKT1 also plays a key role in the regulation of both muscle cell hypertrophy and atrophy. AKT1 activity is required for physiologic cardiac growth in response to IGF1 stimulation or exercise training. In contrast, AKT1 activity was found to antagonize pathologic cardiac growth that occurs in response to endothelin 1 stimulation or pressure overload. AKT1 selectively promotes physiological cardiac growth while AKT2 selectively promotes insulin-stimulated cardiac glucose metabolism. AKT1 deletion prevented tumor initiation as well as tumor progression, coincident with decreased Akt signaling in tumor tissues. AKT1 is the primary Akt isoform activated by mutant K-ras in lung tumors, and that AKT3 may oppose AKT1 in lung tumorigenesis and lung tumor progression. A number of separate studies have implicated AKT1 as an inhibitor of breast epithelial cell motility and invasion. AKT1 may have a dual role in tumorigenesis, acting not only pro-oncogenically by suppressing apoptosis but also anti-oncogenically by suppressing invasion and metastasis.Cancer ImmunotherapyImmune CheckpointImmunotherapyTargeted Therapy

Fumarase is an enzyme that catalyze the reversible hydration dehydration of fumarate to S-malate and is involved in the tricarboxylic acid or Krebs cycle. Fumarase exists in both form, cytosolic formand N-terminal extend mitochondrial form. The N-terminal extended form is targeted to the mitochondrion, where the removal of the extension is the same form as in the cytoplasm. Fumarase is thought to act as a tumor suppressor, which deficiency can lead to progressive encephalopathy, cerebral atrophy and development delay.

E3 ubiquitin ligase. Mediates the ubiquitination and subsequent proteasomal degradation of CKM, GMEB1 and HIBADH. Regulates the proteasomal degradation of muscle proteins under amino acid starvation, where muscle protein is catabolized to provide other organs with amino acids. Inhibits de novo skeletal muscle protein synthesis under amino acid starvation. Regulates proteasomal degradation of cardiac troponin I TNNI3 and probably of other sarcomeric-associated proteins. May play a role in striated muscle atrophy and hypertrophy by regulating an anti-hypertrophic PKC-mediated signaling pathway. May regulate the organization of myofibrils through TTN in muscle cells.

Phosphorylase b kinase gamma catalytic chain, skeletal muscle isoform, also known as Phosphorylase kinase subunit gamma-1 and PHKG1, is a member of the protein kinase superfamily and CAMK Ser Thr protein kinase family. PHKG1 is the catalytic member of a 16 subunit protein kinase complex that contains equimolar ratios of 4 subunit types. The complex is a crucial glycogenolytic regulatory enzyme. Muscle glycogenosis caused by phosphorylase kinase (Phk) deficiency may lead to exercise intolerance, weakness and musculatur atrophy. The gene encoding the muscle isoform of the Phk gamma subunit (gamma M) is one of the candidate genes in which mutations responsible for this condition should be sought. Muscle-specific deficiency of Phk causes glycogen storage disease, clinically manifesting in exercise intolerance with early fatiguability, pain, cramps and occasionally myoglobinuria.

E3 ubiquitin ligase. Mediates the ubiquitination and subsequent proteasomal degradation of CKM, GMEB1 and HIBADH. Regulates the proteasomal degradation of muscle proteins under amino acid starvation, where muscle protein is catabolized to provide other organs with amino acids. Inhibits de novo skeletal muscle protein synthesis under amino acid starvation. Regulates proteasomal degradation of cardiac troponin I TNNI3 and probably of other sarcomeric-associated proteins. May play a role in striated muscle atrophy and hypertrophy by regulating an anti-hypertrophic PKC-mediated signaling pathway. May regulate the organization of myofibrils through TTN in muscle cells.

SMNDC1 gene is a paralog of SMN1 gene, which encodes the survival motor neuron protein, mutations in which are cause of autosomal recessive proximal spinal muscular atrophy. SMNDC1 is a nuclear protein that has been identified as a constituent of the spliceosome complex. SMNDC1 gene is differentially expressed, with abundant levels in skeletal muscle, and may share similar cellular function as the SMN1 gene. SMNDC1 is necessary for spliceosome assembly. Its overexpression causes apoptosis.

UBE1, also known as UBA1, belongs to the ubiquitin-activating E1 family. UBE1 gene complements an X-linked mouse temperature-sensitive defect in DNA synthesis, and thus may function in DNA repair. It is part of a gene cluster on chromosome Xp11.23. UBE1 catalyzes the first step in ubiquitin conjugation to mark cellular proteins for degradation. It also catalyzes the first step in ubiquitin conjugation to mark cellular proteins for degradation by first adenylating its C-terminal glycine residue with ATP, and thereafter linking this residue to the side chain of a cysteine residue in E1, yielding a ubiquitin-E1 thioester and free AMP. Defects in UBA1 can cause spinal muscular atrophy X-linked type 2 (SMAX2), also known as X-linked lethal infantile spinal muscular atrophy, distal X-linked arthrogryposis multiplex congenita or X-linked arthrogryposis type 1 (AMCX1). Spinal muscular atrophy refers to a group of neuromuscular disorders characterized by degeneration of the anterior horn cells of the spinal cord, leading to symmetrical muscle weakness and atrophy. SMAX2 is a lethal infantile form presenting with hypotonia, areflexia, and multiple congenital contractures.

Serpina3n may represent a circulating biomarker of muscle atrophy associated with GC and, broadly, a reflection of dynamic changes in muscle mass. Serpina3n blocks endogenous increases in the activity of select skeletal muscle resident proteases during injury or dystrophic disease, which stabilizes the sarcolemma leading to less myofiber degeneration and increased regeneration.