Browsing Pathways

The members of the large family of matricellular proteins including thrombospondin-1 (TSP1) play important roles in genesis and remodeling of multiple tissues including cartilage and vasculature. TSP1 is one of the important pivots that regulate vascular tissue homeostasis whereas its key function is the negative control of angiogenesis. TSP1 was the first naturally occurring protein inhibitor of angiogenesis to be identified; its anti-angiogenic effects have since been established in a multitude of experimental models and linked to specific epitopes in the multi-domain, multi-functional TSP1 molecule. TSP1 is the first identified, and therefore best studied thrombospondin family representative, its structure is thus considered as prototype for the other family members. In the thrombospondin family, another member, TSP2 has a similar domain structure and, non-surprisingly, its functions significantly overlap with those of TSP1. Specifically, both TSP1 and TSP2 potently inhibit angiogenesis.

Triosephosphate isomerase deficiency is a genetic disorder caused by a mutation in the TPI1 gene. The mutation of this gene causes the production of enzymes that are unstable or enzymes that have reduced activity. This means that cells have reduced energy supplies as glycolysis is compromised. This disorder causes anemia, movement problems and muscle weakness. As a result of the lack of red blood cells to carry oxygen through the body, patients may experience fatigue and shortness of breath. Movement problems appear in early infancy, typically before the age of 2 in patients with this disorder. Treatment includes blood transfusions.

Triosephosphate isomerase deficiency is a genetic disorder caused by a mutation in the TPI1 gene. The mutation of this gene causes the production of enzymes that are unstable or enzymes that have reduced activity. This means that cells have reduced energy supplies as glycolysis is compromised. This disorder causes anemia, movement problems and muscle weakness. As a result of the lack of red blood cells to carry oxygen through the body, patients may experience fatigue and shortness of breath. Movement problems appear in early infancy, typically before the age of 2 in patients with this disorder. Treatment includes blood transfusions.

Trifunctional protein deficiency is a condition caused by mutations in the genes HADHA and HADHB. The enzyme affected is required to metabolize long-chain fatty acids, which makes a patients ability to convert fats to energy very difficult. This is exacerbated by periods without food. The symptoms associated with this disorder differ depending on when they appear in a patient. In infancy, symptoms would include lethargy, hypoglycaemia and hypotonia. Infants are also at higher risk for sudden death and heart problems. Later onset trifunctional protein deficiency symptoms also include hypotonia, but also include breakdown of muscle tissue and peripheral neuropathy. Treatment includes a low-fat, high-carbohydrate diet and avoiding fasting, as this can induce symptoms of this condition.

Trifunctional protein deficiency is a condition caused by mutations in the genes HADHA and HADHB. The enzyme affected is required to metabolize long-chain fatty acids, which makes a patients ability to convert fats to energy very difficult. This is exacerbated by periods without food. The symptoms associated with this disorder differ depending on when they appear in a patient. In infancy, symptoms would include lethargy, hypoglycaemia and hypotonia. Infants are also at higher risk for sudden death and heart problems. Later onset trifunctional protein deficiency symptoms also include hypotonia, but also include breakdown of muscle tissue and peripheral neuropathy. Treatment includes a low-fat, high-carbohydrate diet and avoiding fasting, as this can induce symptoms of this condition.

Transaldolase deficiency, also known as Eyaid syndrome or TALDO deficiency, is a desease caused by homozygous or compound heterozygous mutations in the TALDO1 gene that encodes for transaldolase. The mutation found in one study was a base pair deletion leading to a premature truncation of the protein, preventing its activity in the cell. Other mutations reported in other studies include other deletions or homozygous base pair substitutions that cause a misfolded and non-functional protein. Transaldolase is an enzyme that reversibly converts D-erythrose 4-phosphate and fructose 6-phosphate to D-sedoheptulose 7-phosphate and D-glyceraldehyde 3-phosphate, as a part of the pentose phosphate pathway. Almost all affected patients show hepatosplenomegaly, liver dysfunction, low counts for all blood cell types, cardiac defects, and come from consanguinous families. They also show dysmorphic features, including a triangular face, low set ears, and a wide mouth with thin lips. Other signs include abnormal concentrations of polyols in urine and plasma, as well as ribose-, xylulose-, and ribulose-5-phosphate being elevated in urine.

Transaldolase deficiency, also known as Eyaid syndrome or TALDO deficiency, is a desease caused by homozygous or compound heterozygous mutations in the TALDO1 gene that encodes for transaldolase. The mutation found in one study was a base pair deletion leading to a premature truncation of the protein, preventing its activity in the cell. Other mutations reported in other studies include other deletions or homozygous base pair substitutions that cause a misfolded and non-functional protein. Transaldolase is an enzyme that reversibly converts D-erythrose 4-phosphate and fructose 6-phosphate to D-sedoheptulose 7-phosphate and D-glyceraldehyde 3-phosphate, as a part of the pentose phosphate pathway. Almost all affected patients show hepatosplenomegaly, liver dysfunction, low counts for all blood cell types, cardiac defects, and come from consanguinous families. They also show dysmorphic features, including a triangular face, low set ears, and a wide mouth with thin lips. Other signs include abnormal concentrations of polyols in urine and plasma, as well as ribose-, xylulose-, and ribulose-5-phosphate being elevated in urine.

Hypoxia-inducible factor In many tumours, oxygen availability becomes limited (hypoxia) very quickly during cancer development. The major regulator of the response to hypoxia is the HIF transcription factor. Under normal oxygen levels, the protein levels of HIF alpa is very low due to constant degradation, mediated by a sequence of post-translational modification events catalyzed by the enzymes PHD1,2 and 3, (also known as EglN2,1 and 3). Under hypoxic conditions, HIF alpha escapes hydroxylation and degration. Succinate dehydrogenase (SDH) is a collection of housekeeping genes (SDHA,B,C,D), but mutations in those genes allows for succinate to accumulate and cross the mitochondrial barrier through a dicarboxylate carrier. Once in the cytosol, it inhibits the activity of the PHD1,2 and 3 since succinate is a product of the enzyme, it acts as feedback inhibition.