SECISBP2

Description

The SECISBP2 (SECIS binding protein 2) is a protein-coding gene located on chromosome 9.

SECIS-binding protein 2 (SBP2) is a protein encoded by the SECISBP2 gene in humans. It functions as a SECIS binding protein, crucial for the incorporation of selenocysteine into proteins. This process requires a SECIS element in mRNA, a selenocysteine-specific translation elongation factor, and a SECIS binding protein. Together, these elements enable the decoding of a UGA codon as selenocysteine. Although SBP2 is a nuclear protein, experimental evidence suggests it also exists in the cytoplasm. Mutations in the SECISBP2 gene can lead to reduced activity of specific thyroxine deiodinases, which are selenocysteine-containing enzymes, and ultimately disrupt thyroid hormone metabolism.

SECISBP2 is an mRNA-binding protein that binds to the SECIS (selenocysteine insertion sequence) element present in the 3'-UTR of mRNAs encoding selenoproteins. This binding facilitates the incorporation of the rare amino acid selenocysteine. SECISBP2 and EEFSEC work together to insert selenocysteine at UGA codons. SECISBP2 specifically binds the SECIS sequence once the 80S ribosome encounters an in-frame UGA codon. It then contacts the RPS27A/eS31 of the 40S ribosome before ribosome stalling. GTP-bound EEFSEC delivers selenocysteinyl-tRNA(Sec) to the 80S ribosome, adopting a preaccommodated state conformation. After GTP hydrolysis, EEFSEC dissociates, selenocysteinyl-tRNA(Sec) accommodates, and peptide bond synthesis and selenoprotein elongation occur.

SECISBP2 is also known as SBP2, THMA1.

Associated Diseases

• Short stature-delayed bone age due to thyroid hormone metabolism deficiency
• Thyroid hormone metabolism, abnormal