Nondenaturing two-dimensional electrophoretic analysis of loop-sheet polymerization of serpin, squamous cell carcinoma antigen-2.
Two homologous serine proteinase inhibitors (serpins), squamous cell carcinoma (SCC) antigen-1 and -2 were separated by nondenaturing two-dimensional electrophoresis combined with immunostaining to acquire further information on these proteins under physiological conditions. Polymers of SCC antigen-2 were detected in cytosolic extracts prepared from tumor tissues. The polymer formation of SCC antigen-2 was apparently decreased and the SCC antigen-2-synthetic peptide binary complexes were newly formed by the addition of synthetic peptide with sequences corresponding to residues from P14 to P2 in the reactive center loop of SCC antigen-2. On the other hand, the incubation with synthetic peptides having the sequence of the reactive center loop of SCC antigen-1 or antithrombin had no effect on polymerization of SCC antigen-2. These data suggest that the polymerization of SCC antigen-2 may occur spontaneously in vivo by the loop-sheet mechanism of serpin.
Nawata
S
S
Department of Obstetrics and Gynecology, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Ube, 755-8505 Japan. obgyn@po.cc.yamaguchi-u.ac.jp
Suminami
Y
Y
Hirakawa
H
H
Murakami
A
A
Ogata
H
H
Numa
F
F
Fujimoto
M
M
Tanaka
T
T
Nakamura
K
K
Kato
H
H
D000951:Antigens, Neoplasm / Q000032:analysis*; D000991:Antithrombins / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D006801:Humans; D010455:Peptides / Q000032:analysis; D011108:Polymers; D011489:Protein Denaturation; D015843:Serpins / Q000032:analysis*
D000951:Antigens, Neoplasm; D000991:Antithrombins; D014408:Biomarkers, Tumor; D010455:Peptides; D011108:Polymers; D015843:Serpins; C051072:squamous cell carcinoma-related antigen