1. Calponin isoforms CNN 1, CNN 2 and CNN 3: Regulators for actin cytoskeleton functions in smooth muscle and non-muscle cells
- Author
-
Rong Liu and Jian Ping Jin
- Subjects
0301 basic medicine ,Myocytes, Smooth Muscle ,Calponin ,macromolecular substances ,Myosins ,Article ,Structure-Activity Relationship ,03 medical and health sciences ,0302 clinical medicine ,Cell Movement ,Genetics ,Humans ,Protein Isoforms ,Myocyte ,Cytoskeleton ,Actin ,biology ,Calcium-Binding Proteins ,Microfilament Proteins ,General Medicine ,Smooth muscle contraction ,musculoskeletal system ,Actin cytoskeleton ,Cell biology ,Calponin 1 ,Actin Cytoskeleton ,Calponin 2 ,030104 developmental biology ,Organ Specificity ,030220 oncology & carcinogenesis ,biology.protein ,Mechanoreceptors ,Muscle Contraction - Abstract
Calponin is an actin filament-associated regulatory protein expressed in smooth muscle and multiple types of non-muscle cells. Three homologous genes, CNN1, CNN2 and CNN3, encoding calponin isoforms 1, 2, and 3, respectively, are present in vertebrate species. All three calponin isoforms are actin-binding proteins with functions in inhibiting actin-activated myosin ATPase and stabilizing the actin cytoskeleton, while each isoform executes different physiological roles based on their cell type-specific expressions. Calponin 1 is specifically expressed in smooth muscle cells and plays a role in fine-tuning smooth muscle contractility. Calponin 2 is expressed in both smooth muscle and non-muscle cells and regulates multiple actin cytoskeleton-based functions. Calponin 3 participates in actin cytoskeleton-based activities in embryonic development and myogenesis. Phosphorylation has been extensively studied for the regulation of calponin functions. Cytoskeleton tension regulates the transcription of CNN2 gene and the degradation of calponin 2 protein. This review summarizes our knowledge learned from studies over the past three decades, focusing on the evolutionary lineage of calponin isoform genes, their tissue- and cell type-specific expressions, structure-function relationships, and mechanoregulation.
- Published
- 2016