Mammalian Actins: Isoform-Specific Functions and Diseases

Abstract

Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous network enabling dynamic processes of cells and simultaneously providing structure. Mammals have six actin isoforms that are very conserved and thus share common functions. Tissue-specific expression in part underlies their differential roles, but actin isoforms also coexist in various cell types and tissues, suggesting specific functions and preferential interaction partners. Gene deletion models, antibody-based staining patterns, gene silencing effects, and the occurrence of isoform-specific mutations in certain diseases have provided clues for specificity on the subcellular level and its consequences on the organism level. Yet, the differential actin isoform functions are still far from understood in detail. Biochemical studies on the different isoforms in pure form are just emerging, and investigations in cells have to deal with a complex and regulated system, including compensatory actin isoform expression.

Laryngeal Transcriptomic Insights into Echolocation Call Frequency Divergence in Closely Related Rhinolophus Species

“…Contrary to our third hypothesis, molecular evolutionary analysis shows that the ACTC1 coding sequence is highly conserved among the closely related species analyzed, with no signals of positive selection detected ( Table S8 ). This extreme conservation matches its fundamental role as a core structural protein in muscle contraction, where amino acid sequences are subject to strong purifying constraints [ 88 ]. Therefore, ACTC1 likely contributes to echolocation frequency divergence by differentially regulating expression in laryngeal muscles or altering interactions with other contraction-related proteins, rather than through coding-sequence mutations.…”

Laryngeal Transcriptomic Insights into Echolocation Call Frequency Divergence in Closely Related Rhinolophus Species

“…Contrary to our third hypothesis, molecular evolutionary analysis shows that the ACTC1 coding sequence is highly conserved among the closely related species analyzed, with no signals of positive selection detected ( Table S8 ). This extreme conservation matches its fundamental role as a core structural protein in muscle contraction, where amino acid sequences are subject to strong purifying constraints [ 88 ]. Therefore, ACTC1 likely contributes to echolocation frequency divergence by differentially regulating expression in laryngeal muscles or altering interactions with other contraction-related proteins, rather than through coding-sequence mutations.…”

Colocalization Analysis of Cytoplasmic Actin Isoforms Distribution in Endothelial Cells

“…Many authors suggested there are differences in functions of β- and γ-actin [ 1 , 8 , 10 , 25 , 26 ]. In particular, β-actin functions as an essential regulator of gut barrier integrity in vivo and plays a tissue protective role during mucosal injury and inflammation [ 27 ].…”

Wound Healing Activity of Nanoclay/Spring Water Hydrogels

“…Morphology of fibroblasts during wound healing is very important, since it gives information about migration and adhesion of cells. F-actin filaments facilitate cell–cell interaction and tissue regeneration [ 124 ]. In all samples, regardless of the type of sample with which fibroblasts were put in contact with, NHDF showed typical fusiform morphology.…”

Laryngeal Transcriptomic Insights into Echolocation Call Frequency Divergence in Closely Related Rhinolophus Species

“…Contrary to our third hypothesis, molecular evolutionary analysis shows that the ACTC1 coding sequence is highly conserved among the closely related species analyzed, with no signals of positive selection detected ( Table S8 ). This extreme conservation matches its fundamental role as a core structural protein in muscle contraction, where amino acid sequences are subject to strong purifying constraints [ 88 ]. Therefore, ACTC1 likely contributes to echolocation frequency divergence by differentially regulating expression in laryngeal muscles or altering interactions with other contraction-related proteins, rather than through coding-sequence mutations.…”

Colocalization Analysis of Cytoplasmic Actin Isoforms Distribution in Endothelial Cells

“…Many authors suggested there are differences in functions of β- and γ-actin [ 1 , 8 , 10 , 25 , 26 ]. In particular, β-actin functions as an essential regulator of gut barrier integrity in vivo and plays a tissue protective role during mucosal injury and inflammation [ 27 ].…”

Wound Healing Activity of Nanoclay/Spring Water Hydrogels

“…Morphology of fibroblasts during wound healing is very important, since it gives information about migration and adhesion of cells. F-actin filaments facilitate cell–cell interaction and tissue regeneration [ 124 ]. In all samples, regardless of the type of sample with which fibroblasts were put in contact with, NHDF showed typical fusiform morphology.…”

Laryngeal Transcriptomic Insights into Echolocation Call Frequency Divergence in Closely Related Rhinolophus Species

“…Contrary to our third hypothesis, molecular evolutionary analysis shows that the ACTC1 coding sequence is highly conserved among the closely related species analyzed, with no signals of positive selection detected ( Table S8 ). This extreme conservation matches its fundamental role as a core structural protein in muscle contraction, where amino acid sequences are subject to strong purifying constraints [ 88 ]. Therefore, ACTC1 likely contributes to echolocation frequency divergence by differentially regulating expression in laryngeal muscles or altering interactions with other contraction-related proteins, rather than through coding-sequence mutations.…”

Colocalization Analysis of Cytoplasmic Actin Isoforms Distribution in Endothelial Cells

“…Many authors suggested there are differences in functions of β- and γ-actin [ 1 , 8 , 10 , 25 , 26 ]. In particular, β-actin functions as an essential regulator of gut barrier integrity in vivo and plays a tissue protective role during mucosal injury and inflammation [ 27 ].…”

Wound Healing Activity of Nanoclay/Spring Water Hydrogels

“…Morphology of fibroblasts during wound healing is very important, since it gives information about migration and adhesion of cells. F-actin filaments facilitate cell–cell interaction and tissue regeneration [ 124 ]. In all samples, regardless of the type of sample with which fibroblasts were put in contact with, NHDF showed typical fusiform morphology.…”