Group:MUZIC:MLP

Introduction

The Cystein and glycine-rich protein 3 (CSRP3), or as also known as Muscle LIM Protein (MLP), is one of the three CSRP family members identified in vertebrates. CSRP3 has been identified muscle and cardiac cells^[1]. The three family members contain 192-194 residues and two LIM domains adjacent to a flexible glycine-rich linker. Each LIM domain comprises two Zn-binding motifs CCHC and CCCC representing a structural and presumably functional independent unit.

Sequence Annotation

CSRP3 comprises 194 aminoacids with two 52 residue LIM domains. Each of them is followed by glycine reach sequences of about 10-20 residues UNIPROT (CSRP3_HUMAN).

Structures

LIM domains have been intensively characterized using NMR. The two LIM domains of CSRP3 have been determined by NMR (LIM1: 2O10 and LIM2: 2O13 )

Function and Interactions

All three CSRPs are associated with the actin cytoskeleton and have similar functions in different muscle varieties. CSRP3 is localized in Z and M-lines in striated muscles. The interactions of CSRP3 with telethonin has been reported previously^[2], ^[3], however recent reports demonstrate that this interaction is not existing ^[4]. CSRP3 is mainly interacting with α-actinin 2 as well as has been suggested to interact with βI-spectrin, N-RAP (Nebulin-related-anchoring protein) and cofilin2 (CFL2), underlying the essential role of CSRP3 as a scaffold protein in the sarcomere. During myofibrilogenesis CSRP3 has been suggested to form complexes with the muscle helix-loop-helix transcription factors MyoD, MRF4 and myogenin ^[5].

Pathology

Mutations on the first LIM domain have been linked to familial hypertrophic cardiomyopathy (HCM). All of them (L44P, S54R, E55G, C58G) are related to the proper binding of Zinc to the protein, thus causing conformational alterations. Familial hypertrophic cardiomyopathy is a hereditary heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death ^[6]. The mutation W4R in CSRP3 has been reported to cause dilated cardiomyopathy of type 1Mv(DCM). Dilated cardiomyopathy is a disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia and patients have the risk of premature death ^[7]. However a more recent report demonstrates that the W4R mutation is not sufficient to cause DCM ^[8].

References

1. ↑ Fung YW, Wang RX, Heng HH, Liew CC. Mapping of a human LIM protein (CLP) to human chromosome 11p15.1 by fluorescence in situ hybridization. Genomics. 1995 Aug 10;28(3):602-3. PMID:7490106 doi:http://dx.doi.org/10.1006/geno.1995.1200
2. ↑ Knoll R, Hoshijima M, Hoffman HM, Person V, Lorenzen-Schmidt I, Bang ML, Hayashi T, Shiga N, Yasukawa H, Schaper W, McKenna W, Yokoyama M, Schork NJ, Omens JH, McCulloch AD, Kimura A, Gregorio CC, Poller W, Schaper J, Schultheiss HP, Chien KR. The cardiac mechanical stretch sensor machinery involves a Z disc complex that is defective in a subset of human dilated cardiomyopathy. Cell. 2002 Dec 27;111(7):943-55. PMID:12507422
3. ↑ Zou P, Pinotsis N, Lange S, Song YH, Popov A, Mavridis I, Mayans OM, Gautel M, Wilmanns M. Palindromic assembly of the giant muscle protein titin in the sarcomeric Z-disk. Nature. 2006 Jan 12;439(7073):229-33. PMID:16407954 doi:10.1038/nature04343
4. ↑ Geier C, Gehmlich K, Ehler E, Hassfeld S, Perrot A, Hayess K, Cardim N, Wenzel K, Erdmann B, Krackhardt F, Posch MG, Osterziel KJ, Bublak A, Nagele H, Scheffold T, Dietz R, Chien KR, Spuler S, Furst DO, Nurnberg P, Ozcelik C. Beyond the sarcomere: CSRP3 mutations cause hypertrophic cardiomyopathy. Hum Mol Genet. 2008 Sep 15;17(18):2753-65. Epub 2008 May 27. PMID:18505755 doi:10.1093/hmg/ddn160
5. ↑ Geier C, Gehmlich K, Ehler E, Hassfeld S, Perrot A, Hayess K, Cardim N, Wenzel K, Erdmann B, Krackhardt F, Posch MG, Osterziel KJ, Bublak A, Nagele H, Scheffold T, Dietz R, Chien KR, Spuler S, Furst DO, Nurnberg P, Ozcelik C. Beyond the sarcomere: CSRP3 mutations cause hypertrophic cardiomyopathy. Hum Mol Genet. 2008 Sep 15;17(18):2753-65. Epub 2008 May 27. PMID:18505755 doi:10.1093/hmg/ddn160
6. ↑ Geier C, Perrot A, Ozcelik C, Binner P, Counsell D, Hoffmann K, Pilz B, Martiniak Y, Gehmlich K, van der Ven PF, Furst DO, Vornwald A, von Hodenberg E, Nurnberg P, Scheffold T, Dietz R, Osterziel KJ. Mutations in the human muscle LIM protein gene in families with hypertrophic cardiomyopathy. Circulation. 2003 Mar 18;107(10):1390-5. PMID:12642359
7. ↑ Knoll R, Hoshijima M, Hoffman HM, Person V, Lorenzen-Schmidt I, Bang ML, Hayashi T, Shiga N, Yasukawa H, Schaper W, McKenna W, Yokoyama M, Schork NJ, Omens JH, McCulloch AD, Kimura A, Gregorio CC, Poller W, Schaper J, Schultheiss HP, Chien KR. The cardiac mechanical stretch sensor machinery involves a Z disc complex that is defective in a subset of human dilated cardiomyopathy. Cell. 2002 Dec 27;111(7):943-55. PMID:12507422
8. ↑ Geier C, Gehmlich K, Ehler E, Hassfeld S, Perrot A, Hayess K, Cardim N, Wenzel K, Erdmann B, Krackhardt F, Posch MG, Osterziel KJ, Bublak A, Nagele H, Scheffold T, Dietz R, Chien KR, Spuler S, Furst DO, Nurnberg P, Ozcelik C. Beyond the sarcomere: CSRP3 mutations cause hypertrophic cardiomyopathy. Hum Mol Genet. 2008 Sep 15;17(18):2753-65. Epub 2008 May 27. PMID:18505755 doi:10.1093/hmg/ddn160