In:
Journal of Cell Science, The Company of Biologists, Vol. 117, No. 24 ( 2004-11-15), p. 5781-5789
Abstract:
Parts of the PEVK (Pro-Glu-Val-Lys) domain of the skeletal muscle isoform of the giant intrasarcomeric protein titin have been shown to bind F-actin. However, the mechanisms and physiological function of this are poorly understood. To test for actin binding along PEVK, we expressed contiguous N-terminal (PEVKI), middle (PEVKII), and C-terminal (PEVKIII) PEVK segments of the human soleus muscle isoform. We found a differential actin binding along PEVK in solid-state binding, cross-linking and in vitro motility assays. The order of apparent affinity is PEVKII & gt;PEVKI & gt;PEVKIII. To explore which sequence motifs convey the actin-binding property, we cloned and expressed PEVK fragments with different motif structure: PPAK, polyE-rich and pure polyE fragments. The polyE-containing fragments had a stronger apparent actin binding, suggesting that a local preponderance of polyE motifs conveys an enhanced local actin-binding property to PEVK. The actin binding of PEVK may serve as a viscous bumper mechanism that limits the velocity of unloaded muscle shortening towards short sarcomere lengths. Variations in the motif structure of PEVK might be a method of regulating the magnitude of the viscous drag.
Type of Medium:
Online Resource
ISSN:
1477-9137
,
0021-9533
Language:
English
Publisher:
The Company of Biologists
Publication Date:
2004
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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