VEGF121 Human Active Protein

This gene is a member of the PDGF/VEGF growth factor family and encodes a protein that is often found as a disulfide linked homodimer. This protein is a glycosylated mitogen that specifically acts on endothelial cells and has various effects, including mediating increased vascular permeability, inducing angiogenesis, vasculogenesis and endothelial cell growth, promoting cell migration, and inhibiting apoptosis. Elevated levels of this protein is linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in this gene have been associated with proliferative and nonproliferative diabetic retinopathy. Alternatively spliced transcript variants, encoding either freely secreted or cell-associated isoforms, have been characterized. There is also evidence for the use of non-AUG (CUG) translation initiation sites upstream of, and in-frame with the first AUG, leading to additional isoforms. [provided by RefSeq, Jul 2008]

Function: Growth factor active in angiogenesis, vasculogenesis and endothelial cell growth. Induces endothelial cell proliferation, promotes cell migration, inhibits apoptosis and induces permeabilization of blood vessels. Binds to the FLT1/VEGFR1 and KDR/VEGFR2 receptors, heparan sulfate and heparin. NRP1/Neuropilin-1 binds isoforms VEGF-165 and VEGF-145. Isoform VEGF165B binds to KDR but does not activate downstream signaling pathways, does not activate angiogenesis and inhibits tumor growth. Ref.27 Ref.30 Ref.33

Subunit structure: Homodimer; disulfide-linked. Also found as heterodimer with PGF

By similarity.

Subcellular location: Secreted. Note: VEGF121 is acidic and freely secreted. VEGF165 is more basic, has heparin-binding properties and, although a signicant proportion remains cell-associated, most is freely secreted. VEGF189 is very basic, it is cell-associated after secretion and is bound avidly by heparin and the extracellular matrix, although it may be released as a soluble form by heparin, heparinase or plasmin. Ref.26 Ref.28 Ref.32

Tissue specificity: Isoform VEGF189, isoform VEGF165 and isoform VEGF121 are widely expressed. Isoform VEGF206 and isoform VEGF145 are not widely expressed.

Induction: Regulated by growth factors, cytokines, gonadotropins, nitric oxide, hypoxia, hypoglycemia and oncogenic mutations.

Involvement in disease: Microvascular complications of diabetes 1 (MVCD1) [MIM:603933]: Pathological conditions that develop in numerous tissues and organs as a consequence of diabetes mellitus. They include diabetic retinopathy, diabetic nephropathy leading to end-stage renal disease, and diabetic neuropathy. Diabetic retinopathy remains the major cause of new-onset blindness among diabetic adults. It is characterized by vascular permeability and increased tissue ischemia and angiogenesis.Note: Disease susceptibility is associated with variations affecting the gene represented in this entry.

Sequence similarities: Belongs to the PDGF/VEGF growth factor family.

Sequence caution: The sequence AAC63102.1 differs from that shown. Reason: Erroneous initiation. The sequence AAC63143.1 differs from that shown. Reason: Unusual initiator. The initiator methionine is coded by a non-canonical CTG leucine codon.The sequence CAC19512.2 differs from that shown. Reason: Unusual initiator. The initiator methionine is coded by a non-canonical CTG leucine codon.The sequence CAC19516.2 differs from that shown. Reason: Unusual initiator. The initiator methionine is coded by a non-canonical CTG leucine codon.