Disease relevance of Cnn1

• Calponin and caldesmon cellular domains in reacting microvessels following traumatic brain injury [1].
• Cotransfecting a dominant-negative SRF construct attenuated smooth muscle-specific enhancer activity, and transducing smooth muscle cells with adenovirus harboring the dominant-negative SRF construct selectively reduced steady-state expression of endogenous smooth muscle calponin [2].
• DESIGN: Aortic calponin gene expression was studied after chronic exogenous Ang II administration and in Goldblatt hypertension [3].
• In particular, calponin gene expression in 2K1C rats was studied both at 1 week (2K1C-HR, high renin) and 4 weeks after the onset of hypertension, when plasma renin activity (PRA) was returned to normal values (2K1C-NR, normal renin) [3].
• Hyperplasia of myoepithelial cells expressing calponin during atrophy of the rat parotid gland induced by duct ligation [4].

High impact information on Cnn1

• Calponin and SM22 alpha are major components of differentiated smooth muscle and potential regulators of actin cytoskeleton interactions [5].
• Calponin repeats regulate actin filament stability and formation of podosomes in smooth muscle cells [5].
• We provide evidence for the existence of two functionally distinct actin filament populations and introduce a molecular mechanism for the stabilization of the actin cytoskeleton by the unique actin-binding interface formed by calponin family-specific CLIK23 repeats [5].
• Smooth muscle calponin is a multifunctional, thin filament-associated protein whose expression is restricted to smooth muscle cell lineages in developing and postnatal tissues [2].
• Site-directed mutagenesis studies suggested that the consensus CArG box mediates much of the intronic enhancer activity; mutating all three CArG elements abolished the ability of SRF to confer enhancer activity on the smooth muscle calponin promoter [2].

Biological context of Cnn1

• Single and double immunocytochemical techniques together with semiquantitative analyses revealed a Cp upregulation in SM at all time frames post-TBI; with the protein migrating from SM cytosol to the vicinity of the cell membrane [1].
• The molecular basis for the autoregulation of calponin by isoform-specific C-terminal tail sequences [6].
• Cell phenotype was determined by immunoblot and immunocytofluorescence using antisera specific for the differentiation markers alpha-actin, myosin, calponin, osteopontin, and phospholamban [7].
• As the 22-kDa fragment contained only T2, the phosphorylation site in T2 appeared to regulate the binding of calponin to F-actin and tropomyosin [8].
• Here we report on smooth muscle-specific enhancer activity within the first intron of smooth muscle calponin [2].

Anatomical context of Cnn1

• Removal of the inhibitory tail resulted in an increased binding and bundling activity, and caused a prominent re-localization of h2 CaP from the peripheral actin network to the central actin stress fibers in transfected A7r5 smooth muscle cells [6].
• Altogether, these results are consistent with an involvement of acidic calponin in dendritic spine plasticity [9].
• Our data show that the intensity of immunolabeling for acidic calponin was clearly increased in the inner one-third of the molecular layer of the dentate gyrus, the site of mossy fiber sprouting, and neo-synaptogenesis, at 1 and 2 weeks after pilocarpine injection (silent period) when the reorganization was taking place [9].
• Cloning and expression of a novel acidic calponin isoform from rat aortic vascular smooth muscle [10].
• To assess the physiological significance and the molecular basis of the calponin-microtubule interaction, we have first studied the solution binding of recombinant acidic calponin to microtubules using quantitative cosedimentation analyses [11].

Associations of Cnn1 with chemical compounds

• In contrast, in chronic pilocarpine-treated animals, when the reorganization was established, the levels of labeling for acidic calponin in the inner molecular layer were similar to those observed in control rats [9].
• Structure-function relations of smooth muscle calponin. The critical role of serine 175 [12].
• These results indicate that the hydroxyl side chain at position 175 of calponin plays a critical role in the binding of calponin to actin and inhibition of the cross-bridge cycling rate [12].
• The effect of endogenous Ang II on aortic calponin mRNA expression was studied in Goldblatt hypertensive rats with (2K1C model), or without (1K1C model) activation of the renin-angiotensin system [3].
• Angiotensin II modulates calponin gene expression in rat vascular smooth muscle cells in vivo [3].

Physical interactions of Cnn1

• Calponin interacts with both the alpha and beta tubulins and only slightly with the tyrosinated and acetylated form of alpha tubulin [13].

Other interactions of Cnn1

• However, while Cp and Cd in SM remained elevated, their levels in En returned to normal at 48 h post-TBI [1].
• However, in contrast to SMCs, TGF-beta did not induce expression of h(1) calponin and SM MHC in non-SMCs [14].
• Several putative functional motifs are present in the protein, including a calponin homology domain, three nuclear localization signals, a consensus P-loop, and a proline-rich region, suggesting that KPL2 has a unique function [15].
• Immunological analyses and reverse transcriptase-polymerase chain reaction indicated that the differentiated cells expressed smooth-muscle-specific marker proteins such as SM-1, SM-2, and SMemb myosin heavy chains, SM-22, basic calponin and alpha-smooth-muscle actin, but not the astrocyte marker glial fibrillary acidic protein [16].
• A longitudinal section of myometrium was removed, total RNA was extracted, and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed for glyceraldehyde phosphate dehydrogenase (GAPDH), calponin, EP2, and FP receptor mRNA expression [17].

Analytical, diagnostic and therapeutic context of Cnn1

• Fractionation of tryptic 32P-labeled peptides by high performance liquid chromatography allowed isolation of three phosphopeptides (designated T1, T2, and T3), each of which was located in three repeating amino acid motifs of calponin [8].
• Sequence analysis showed that plectin contains a highly conserved actin-binding domain, consisting of a pair of calponin-like subdomains [18].
• Using one- or two-dimensional gel electrophoresis followed by the Western blot technique, and by immunofluorescence studies, we have given evidence that calponin is also present in rat and pig brain [19].
• Expression of an acidic isoform of calponin in rat brain: western blots on one- or two-dimensional gels and immunolocalization in cultured cells [20].
• METHODS: Pericyte and SMC differentiation was characterized by immunohistochemistry with antibodies to NG2, desmin, alpha-smooth muscle actin (SMA), calponin, and caldesmon [21].

References