Characterization of type III intermediate filament regulatory protein target epitopes: S-100 (beta and/or alpha) binds the N-terminal head domain; annexin II2-p11(2) binds the rod domain.
We have investigated the interaction of S-100 proteins (beta and/or alpha) and annexin II2-p11(2) with glial fibrillary acidic protein (GFAP) and desmin to have further information on the mechanisms whereby S-100 proteins and annexin II2-p11(2) affect assembly/disassembly of GFAP and desmin intermediate filaments (IFs). Analyses were conducted on either native IF subunits, GFAP or desmin rod domain, or headless GFAP or desmin. Our data indicate that: (i) S-100 proteins bind to GFAP and desmin N-terminal head domain; (ii) annexin II2-p11(2) binds to GFAP rod domain; (iii) annexin II2-p11(2) does not interact with desmin nor affects desmin assembly. The present data suggest that the ability of S-100 proteins to inhibit GFAP and desmin assemblies and to promote the disassembly of preformed GFAP and desmin IFs depends on occupation of a site on the N-terminal head domain of these IF subunit. It is known that the N-terminal head domain is critical for the progression from the stage of GFAP and desmin dimers/tetramers to that of large oligomers. On the other hand, the ability of annexin II2-p11(2) to stimulate GFAP assembly under conditions where this latter is normally hampered (e.g., at alkaline pH values) might depend on annexin II2-p11(2)-induced changes in the structure of GFAP rod domain, possibly as a consequence of charge modifications. By contrast, the inability of annexin II2-p11(2) to bind to desmin would depend on desmin resistance to charge modifications.
Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
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M
Garbuglia
M
M
Verzini
R V
RV
Dimlich
G A
GA
Jamieson
R
R
Donato
D000818:Animals; D017306:Annexin A2 / Q000378:metabolism*; D001665:Binding Sites; D015415:Biomarkers; D002417:Cattle; D002645:Chickens; D003432:Cross-Linking Reagents; D003893:Desmin / Q000096:biosynthesis / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D007382:Intermediate Filaments / Q000378:metabolism*; D008970:Molecular Weight; D009414:Nerve Growth Factors; D010446:Peptide Fragments / Q000032:analysis; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D011489:Protein Denaturation; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*; D013388:Succinimides; D013552:Swine; D014508:Urea; D000099248:S100 Calcium Binding Protein A10
D017306:Annexin A2; D015415:Biomarkers; D003432:Cross-Linking Reagents; D003893:Desmin; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D010446:Peptide Fragments; D010455:Peptides; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D013388:Succinimides; D014508:Urea; D000099248:S100 Calcium Binding Protein A10; C030564:S-100 calcium-binding protein alpha subunit; C019358:disuccinimidyl suberate