Purification, cDNA structure and biological significance of a single insulin-like growth factor-binding domain protein (SIBD-1) identified in the hemocytes of the spider Cupiennius salei

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• 作者：Lucia  ; Kuhn-Nentwig^a ;   ; ^{lucia.kuhn@iee.unibe.ch} ; Carlo R.  ; Largiadè ; r^b ; Kathrin  ; Streitberger^a ; Sathyan  ; Chandru^a ; Tommy  ; Baumann^a ; Urs  ; Kä ; mpfer^c ; Johann  ; Schaller^c ; Stefan  ; Schü ; rch^c ; Wolfgang  ; Nentwig^a
• 关键词：Cupiennius salei ; SIBD-1 ; SIBD-2 ; IGFBP-rP1 ; Tissue expression ; Insulin-like growth factor-binding protein (IGFBP) ; N-Terminal domain
• 刊名：Insect Biochemistry and Molecular Biology
• 出版年：2011
• 出版时间：November 2011
• 年：2011
• 卷：41
• 期：11
• 页码：891-901
• 全文大小：1446 K

文摘

Cupiennius salei single insulin-like growth factor-binding domain protein (SIBD-1), which exhibits an IGFBP N-terminal domain-like profile, was identified in the hemocytes of the spider C. salei. SIBD-1 was purified by RP-HPLC and the sequence determined by a combination of Edman degradation and 5′?? RACE PCR. The peptide (8676.08?Da) is composed of 78 amino acids, contains six intrachain disulphide bridges and carries a modified Thr residue at position 2. SIBD-1 mRNA expression was detected by quantitative real-time PCR mainly in hemocytes, but also in the subesophageal nerve mass and muscle. After infection, the SIBD-1 content in the hemocytes decreases and, simultaneously, the temporal SIBD-1 expression seems to be down-regulated. Two further peptides, SIBD-2 and IGFBP-rP1, also exhibiting IGFBP N-terminal domain variants with unknown functions, were identified on cDNA level in spider hemocytes and venom glands. We conclude that SIBD-1 may play an important role in the immune system of spiders.