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Actinin-associated LIM protein: identification of a domain interaction between PDZ and spectrin-like repeat motifs.

Xia H, Winokur ST, Kuo WL, Altherr MR, Bredt DS - J. Cell Biol. (1997)

Bottom Line: Here, we identify actinin-associated LIM protein (ALP), a novel protein in skeletal muscle that contains an NH2-terminal PDZ domain and a COOH-terminal LIM motif.Biochemical and yeast two-hybrid analyses demonstrate that the PDZ domain of ALP binds to the spectrin-like motifs of alpha-actinin-2, defining a new mode for PDZ domain interactions.Fine genetic mapping studies demonstrate that ALP occurs on chromosome 4q35, near the heterochromatic locus that is mutated in fascioscapulohumeral muscular dystrophy.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of California at San Francisco, San Francisco, California 94143, USA.

ABSTRACT
PDZ motifs are protein-protein interaction domains that often bind to COOH-terminal peptide sequences. The two PDZ proteins characterized in skeletal muscle, syntrophin and neuronal nitric oxide synthase, occur in the dystrophin complex, suggesting a role for PDZ proteins in muscular dystrophy. Here, we identify actinin-associated LIM protein (ALP), a novel protein in skeletal muscle that contains an NH2-terminal PDZ domain and a COOH-terminal LIM motif. ALP is expressed at high levels only in differentiated skeletal muscle, while an alternatively spliced form occurs at low levels in the heart. ALP is not a component of the dystrophin complex, but occurs in association with alpha-actinin-2 at the Z lines of myofibers. Biochemical and yeast two-hybrid analyses demonstrate that the PDZ domain of ALP binds to the spectrin-like motifs of alpha-actinin-2, defining a new mode for PDZ domain interactions. Fine genetic mapping studies demonstrate that ALP occurs on chromosome 4q35, near the heterochromatic locus that is mutated in fascioscapulohumeral muscular dystrophy.

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Sequence analysis of ALP isoforms. (A) Amino acids 5–80 of ALP encode a consensus PDZ domain. Alignment of ALP with  PDZ domains from CLP-36, PSD95, α1-syntrophin, (α1syn), nNOS, and INAD. Histidine 62 of ALP is marked with an asterisk and leucine 78 with a pound sign. (B) Predicted sequences of rat ALP (GenBank/EMBL/DDBJ accession no. AF002281) and human ALP  (hALP) are aligned with two homologous proteins, CLP-36 and RIL. (C) An alternative ALP isoform is expressed in the heart. Schematic model shows the domain structure of ALP and the divergence of ALP between skeletal muscle (hALPSK; accession no.  AF002280) and heart (hALPH; accession no. AF002282). The alignment shows that the central region of ALP is different between skeletal muscle and heart. The accession numbers for ESTs used to construct hALPH are F12229, R20192, AA147575, AA211287, and  D56502. The accession numbers for ESTs encoding the skeletal muscle–specific splice for hALPsk are Z28845, Z19288, and Z28703.
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Figure 2: Sequence analysis of ALP isoforms. (A) Amino acids 5–80 of ALP encode a consensus PDZ domain. Alignment of ALP with PDZ domains from CLP-36, PSD95, α1-syntrophin, (α1syn), nNOS, and INAD. Histidine 62 of ALP is marked with an asterisk and leucine 78 with a pound sign. (B) Predicted sequences of rat ALP (GenBank/EMBL/DDBJ accession no. AF002281) and human ALP (hALP) are aligned with two homologous proteins, CLP-36 and RIL. (C) An alternative ALP isoform is expressed in the heart. Schematic model shows the domain structure of ALP and the divergence of ALP between skeletal muscle (hALPSK; accession no. AF002280) and heart (hALPH; accession no. AF002282). The alignment shows that the central region of ALP is different between skeletal muscle and heart. The accession numbers for ESTs used to construct hALPH are F12229, R20192, AA147575, AA211287, and D56502. The accession numbers for ESTs encoding the skeletal muscle–specific splice for hALPsk are Z28845, Z19288, and Z28703.

Mentions: cDNA clones encoding the full 1.6-kb mRNA were obtained from a rat skeletal muscle cDNA library. The mRNA contains a single ORF of 1,086 bp encoding a protein of 39 kD. Sequence analysis shows that ALP has a homology at the NH2 terminus to PDZ domains. Alignment of ALP with other PDZ domains is shown (Fig. 2 A). The presence of histidine at amino acid 62 suggests that the PDZ domain may be in group I (Brenman and Bredt, 1997; Songyang et al., 1997).


Actinin-associated LIM protein: identification of a domain interaction between PDZ and spectrin-like repeat motifs.

Xia H, Winokur ST, Kuo WL, Altherr MR, Bredt DS - J. Cell Biol. (1997)

Sequence analysis of ALP isoforms. (A) Amino acids 5–80 of ALP encode a consensus PDZ domain. Alignment of ALP with  PDZ domains from CLP-36, PSD95, α1-syntrophin, (α1syn), nNOS, and INAD. Histidine 62 of ALP is marked with an asterisk and leucine 78 with a pound sign. (B) Predicted sequences of rat ALP (GenBank/EMBL/DDBJ accession no. AF002281) and human ALP  (hALP) are aligned with two homologous proteins, CLP-36 and RIL. (C) An alternative ALP isoform is expressed in the heart. Schematic model shows the domain structure of ALP and the divergence of ALP between skeletal muscle (hALPSK; accession no.  AF002280) and heart (hALPH; accession no. AF002282). The alignment shows that the central region of ALP is different between skeletal muscle and heart. The accession numbers for ESTs used to construct hALPH are F12229, R20192, AA147575, AA211287, and  D56502. The accession numbers for ESTs encoding the skeletal muscle–specific splice for hALPsk are Z28845, Z19288, and Z28703.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2139795&req=5

Figure 2: Sequence analysis of ALP isoforms. (A) Amino acids 5–80 of ALP encode a consensus PDZ domain. Alignment of ALP with PDZ domains from CLP-36, PSD95, α1-syntrophin, (α1syn), nNOS, and INAD. Histidine 62 of ALP is marked with an asterisk and leucine 78 with a pound sign. (B) Predicted sequences of rat ALP (GenBank/EMBL/DDBJ accession no. AF002281) and human ALP (hALP) are aligned with two homologous proteins, CLP-36 and RIL. (C) An alternative ALP isoform is expressed in the heart. Schematic model shows the domain structure of ALP and the divergence of ALP between skeletal muscle (hALPSK; accession no. AF002280) and heart (hALPH; accession no. AF002282). The alignment shows that the central region of ALP is different between skeletal muscle and heart. The accession numbers for ESTs used to construct hALPH are F12229, R20192, AA147575, AA211287, and D56502. The accession numbers for ESTs encoding the skeletal muscle–specific splice for hALPsk are Z28845, Z19288, and Z28703.
Mentions: cDNA clones encoding the full 1.6-kb mRNA were obtained from a rat skeletal muscle cDNA library. The mRNA contains a single ORF of 1,086 bp encoding a protein of 39 kD. Sequence analysis shows that ALP has a homology at the NH2 terminus to PDZ domains. Alignment of ALP with other PDZ domains is shown (Fig. 2 A). The presence of histidine at amino acid 62 suggests that the PDZ domain may be in group I (Brenman and Bredt, 1997; Songyang et al., 1997).

Bottom Line: Here, we identify actinin-associated LIM protein (ALP), a novel protein in skeletal muscle that contains an NH2-terminal PDZ domain and a COOH-terminal LIM motif.Biochemical and yeast two-hybrid analyses demonstrate that the PDZ domain of ALP binds to the spectrin-like motifs of alpha-actinin-2, defining a new mode for PDZ domain interactions.Fine genetic mapping studies demonstrate that ALP occurs on chromosome 4q35, near the heterochromatic locus that is mutated in fascioscapulohumeral muscular dystrophy.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of California at San Francisco, San Francisco, California 94143, USA.

ABSTRACT
PDZ motifs are protein-protein interaction domains that often bind to COOH-terminal peptide sequences. The two PDZ proteins characterized in skeletal muscle, syntrophin and neuronal nitric oxide synthase, occur in the dystrophin complex, suggesting a role for PDZ proteins in muscular dystrophy. Here, we identify actinin-associated LIM protein (ALP), a novel protein in skeletal muscle that contains an NH2-terminal PDZ domain and a COOH-terminal LIM motif. ALP is expressed at high levels only in differentiated skeletal muscle, while an alternatively spliced form occurs at low levels in the heart. ALP is not a component of the dystrophin complex, but occurs in association with alpha-actinin-2 at the Z lines of myofibers. Biochemical and yeast two-hybrid analyses demonstrate that the PDZ domain of ALP binds to the spectrin-like motifs of alpha-actinin-2, defining a new mode for PDZ domain interactions. Fine genetic mapping studies demonstrate that ALP occurs on chromosome 4q35, near the heterochromatic locus that is mutated in fascioscapulohumeral muscular dystrophy.

Show MeSH
Related in: MedlinePlus