Related Experiment Video
Updated: Aug 6, 2026
07:51
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Nonmuscle caldesmon: its distribution and involvement in various cellular processes. Review article
R Dabrowska1, N Kulikova, M Gagola
1Department of Muscle Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw. r.dabrowska@nencki.gov.pl
Protoplasma
|February 25, 2005
Summary
Smooth muscle caldesmon and nonmuscle caldesmon share similar terminal domains but differ in their central structure, leading to distinct cellular roles. Nonmuscle caldesmon regulates microfilament dynamics and cell contraction, controlled by calcium/calmodulin and phosphorylation.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Caldesmon is a thin-filament protein involved in regulating actomyosin motor activity.
- Smooth muscle caldesmon and its nonmuscle counterpart share structural similarities in terminal domains but differ in a central alpha-helical fragment.
Purpose of the Study:
- To elucidate the distinct physiological functions of nonmuscle caldesmon based on its structural differences and cellular distribution.
- To explore the mechanisms regulating nonmuscle caldesmon activity, including interactions with actin, tropomyosin, and myosin, and its control by Ca2+/calmodulin and phosphorylation.
Main Methods:
- Comparative molecular anatomy analysis of smooth muscle and nonmuscle caldesmon.
- Investigation of nonmuscle caldesmon interactions with filamentous actin, tropomyosin, and myosin.
- Examination of regulatory mechanisms involving Ca2+/calmodulin and protein kinases.
Main Results:
- Nonmuscle caldesmon directly interacts with actin and tropomyosin, influencing microfilament assembly, dynamics, and stability.
- Nonmuscle caldesmon indirectly inhibits actomyosin interactions, participating in the regulation of cell contraction and intracellular movement.
- Ca2+/calmodulin and phosphorylation by protein kinases are key regulators of nonmuscle caldesmon functions in vertebrates.
Conclusions:
- Structural variations between smooth muscle and nonmuscle caldesmon dictate their specialized roles in cellular processes.
- Nonmuscle caldesmon is a crucial regulator of cytoskeletal organization and cell motility across diverse eukaryotic organisms.
Related Concept Videos
01:10The Role of Actin and Myosin in Non-muscle Cells
Actin and myosin or actomyosin filaments also play a significant role in cells other than those involved in muscle contraction (which occurs within the sarcomere of muscle cells). The mechanism of non-muscle cell contractile bundles was first observed in Dictyostelium and Acanthamoeba. In non-muscle cells, two bundles are commonly found: stress fibers and actomyosin adherence belts. These contractile bundles are smaller and less organized than the ones found in muscle cells. They are held...
01:15Overview of Skeletal Muscle
Skeletal muscles are composed of a bundle of muscle fibers and are attached to bones through tendons. Each skeletal muscle fiber is a single muscle cell. The sarcolemma, the plasma membrane of a skeletal muscle cell, consists of a lipid bilayer and glycocalyx that supports muscle fibers. The sarcolemma extends into the muscle cells to form tubular structures called transverse or T-tubules. Each side of the T-tubules consists of a membrane-bound structure called the sarcoplasmic reticulum,...
01:02Role of Septins
Septins are the recently discovered fourth major protein component of the cytoskeleton, along with microfilaments, microtubules, and intermediate filaments. These proteins can associate with other cytoskeletal filaments and carry out varied roles or can be free-floating in the cytoplasm.
Cellular Functions of Septins
Recent studies have revealed the multifaceted roles of septins in various cellular processes such as cytokinesis, ciliogenesis, and neurogenesis. Septins act as scaffolds and...
Cellular Functions of Septins
Recent studies have revealed the multifaceted roles of septins in various cellular processes such as cytokinesis, ciliogenesis, and neurogenesis. Septins act as scaffolds and...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:13Microscopic Anatomy of Skeletal Muscles
Skeletal muscle cells, also called muscle fibers, are distinctly elongated, multi-nucleated, slender biological units. They are packed with specialized structures designed to facilitate their primary function, which is contraction.
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
00:51Synthesis and Functions of Calcitonin
Calcitonin, a vital polypeptide hormone, regulates calcium levels within body fluids. It is released by the parafollicular cells, also known as C cells, situated in the follicular epithelium of the thyroid gland. Calcitonin responds to fluctuations in blood calcium levels and the influence of gastrointestinal hormones like gastrin and cholecystokinin.
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...