CLONING AND EXPRESSION OF A NOVEL ACIDIC CALPONIN ISOFORM FROM RAT AORTIC VASCULAR SMOOTH-MUSCLE

Citation
D. Applegate et al., CLONING AND EXPRESSION OF A NOVEL ACIDIC CALPONIN ISOFORM FROM RAT AORTIC VASCULAR SMOOTH-MUSCLE, The Journal of biological chemistry, 269(14), 1994, pp. 10683-10690
Citations number
44
Categorie Soggetti
Biology
ISSN journal
00219258
Volume
269
Issue
14
Year of publication
1994
Pages
10683 - 10690
Database
ISI
SICI code
0021-9258(1994)269:14<10683:CAEOAN>2.0.ZU;2-3
Abstract
The actin-binding protein calponin has been implicated in the regulati on of smooth muscle contraction. We have isolated cDNA clones encoding a novel acidic calponin isoform from rat aortic vascular smooth muscl e cells. The initial 273 residues of the deduced 330 amino acid polype ptide (M(r) 36,377) are highly homologous to basic smooth muscle calpo nin isoforms, but the remaining 57 residues at the carboxyl terminus c omprise a unique and strongly acidic domain. The sequence of the acidi c domain shows high homology (93.3% identity) to the partial sequence of HUMXT01244, an unidentified human hippocampal gene product (Adams, M., Dubnick, M., Kerlavgne, A. R., Moreno, R., Kelly, J. M., Utterback , T. R., Nagle, J. W., Fields, C., and Venter, J. C. (1992) Nature 355 , 632-634). Transcripts encoding acidic calponin are expressed in cult ured rat aortic vascular smooth muscle cells and in non-muscle and smo oth muscle tissues of adult rat. Based on its calculated M(r) and the tissue distribution of its expression, acidic calponin is an excellent candidate for a previously detected non-muscle calponin homolog (Take uchi, K., Takahashi, It., Abe, M., Nishida, W, Hiwada, K., Nabeya, T, and Maruyama, It. (1991) J. Biochem. (Tokyo) 109, 311-316). Like basic calponin isoforms, acidic calponin synthesized in a bacterial express ion system bound F-actin. However, unlike basic calponin, the acidic i soform did not interact with Ca2+/calmodulin, indicating a functional distinction between the muscle and non-muscle forms.