SPG21

SPG21 may play a role as a negative regulatory factor in CD4-dependent T-cell activation.

SPG21 Related Areas

Immunology>>Adaptive Immunity>>T Cell>>T Cell Antigen Recognition>>SPG21/ACP33

SPG21 Alternative Names

SPG21, ACP33, BM-019, GL010, MASPARDIN, MAST [Homo sapiens]

Spg21, ACP33, BM-019, C78576, D9Wsu18e, GL010, MAST [Mus musculus]

Summaries for SPG21

Entrez Gene summary for SPG21:

The protein encoded by SPG21 gene was identified by a two-hybrid screen using CD4 as the bait. It binds to the hydrophobic C-terminal amino acids of CD4 which are involved in repression of T cell activation. The interaction with CD4 is mediated by the noncatalytic alpha/beta hydrolase fold domain of this protein. It is thus proposed that this gene product modulates the stimulatory activity of CD4. At least three different transcript variants encoding two different isoforms have been found for SPG21 gene. [provided by RefSeq, Jul 2008]

Wikipedia summary for SPG21:

Maspardin is a protein that in humans is encoded by the SPG21 gene.
The protein encoded by this gene was identified by a two-hybrid screen using CD4 as the bait. It binds to the hydrophobic C-terminal amino acids of CD4 which are involved in repression of T cell activation. The interaction with CD4 is mediated by the noncatalytic alpha/beta hydrolase fold domain of this protein. It is thus proposed that this gene product modulates the stimulatory activity of CD4.

Human SPG21 Protein General Information

 

• Protein names: Spastic paraplegia 21 protein
  Short name=SPG21
• Sequence length: 308 AA.
• Sequence similarities: Belongs to the AB hydrolase superfamily.
• Subunit structure: Interacts with CD4. Interacts with ALDH16A1.
• Subcellular location: Cytoplasm › cytosol. Membrane; Peripheral membrane protein. Endosome membrane; Peripheral membrane protein. Golgi apparatus › trans-Golgi network membrane; Peripheral membrane protein. Note: Partially localized in the cytosol but also accumulated on an intracellular vesicular compartment. Colocalizes with CD4 on endosomal/trans-Golgi network.
• Tissue specificity: Expressed in all tissues tested, including heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Expressed in JCaM1.6, HUT 78 and HeLa cell lines (at protein level).
• Involvement in disease: Defects in SPG21 are the cause of spastic paraplegia autosomal recessive type 21 (SPG21) ; also known as Mast syndrome. Spastic paraplegia is a neurodegenerative disorder characterized by a slow, gradual, progressive weakness and spasticity of the lower limbs. Rate of progression and the severity of symptoms are quite variable. Initial symptoms may include difficulty with balance, weakness and stiffness in the legs, muscle spasms, and dragging the toes when walking. In some forms of the disorder, bladder symptoms (such as incontinence) may appear, or the weakness and stiffness may spread to other parts of the body. SPG21 is associated with dementia and other central nervous system abnormalities. Subtle childhood abnormalities may be present, but the main features develop in early adulthood. The disease is slowly progressive, and cerebellar and extrapyramidal signs are also found in patients with advanced disease. Patients have a thin corpus callosum and white-matter abnormalities.

General information above from UniProt

Function for SPG21 Protein

UniProtKB:

SPG21 may play a role as a negative regulatory factor in CD4-dependent T-cell activation.

Genatlas:

• SPG21 is ligand of CD4 (Zeitlmann 2001)
• SPG21 is aldehyde dehydrogenase ALDH16A1 (Hanna 2009)

Homology for human SPG21

• ortholog to Spg21, Mus musculus
• ortholog to SPG21, Pan troglodytes
• ortholog to Spg21, Rattus norvegicus
• ortholog to spg21, Danio rerio

Phenotype Information for SPG21

• Gene/Locus: ACP33, MAST, SPG21
• Phenotype: Mast syndrome

Phenotype Information for SPG21 from OMIM (Online Mendelian Inheritance in Man)