SEC31 Homolog B (SEC31B)

Sec31b displayed pharmacologic and dynamic behaviors that confirmed its participation with COPII -coated organellesThe full-length cDNA encodes a deduced 1,180-amino acid protein with a calculated molecular mass of 128.7 kD. The N-terminal half contains 7 canonical WD repeats, and the C-terminal half contains proline-rich regions. Full-length SEC31B shares 47.3% identity with SEC31A. Most other SEC31B variants contain exon 13, which has an in-frame stop codon that results in truncated proteins of no more than 53 kD. Northern blot analysis detected 2 or 3 transcripts of about 6.5 kb in all tissues examined, with highest expression in testis. Weakly expressed transcripts of 1.0 and at least 11 kb were also detected. RNA dot blot analysis showed ubiquitous expression, with highest levels in testis and cerebellum.