Cytoskeleton Microfilaments Quiz

Actin monomers (G-actin) add to the growing end of a filament (F-actin) to form microfilaments. This process is regulated by actin-binding proteins (ABPs) like profilin and cofilin.

Tropomyosin and troponin control actin's interaction with myosin.

Microtubules are formed by tubulin heterodimers, and their assembly is regulated by microtubule-associated proteins (MAPs), GTP hydrolysis for stability, and motor proteins like dynein and kinesin facilitating intracellular transport.

<p>Intermediate filaments assemble as coiled-coil dimers to form stable filaments. Their assembly is regulated by phosphorylation and dephosphorylation of specific sites on intermediate filament proteins.</p> Signup and view all the answers

<p>Microfilaments are composed of actin proteins, microtubules are made up of tubulin proteins, and intermediate filaments consist of various proteins depending on the type.</p> Signup and view all the answers

<p>Microtubules play a pivotal role in cell division by forming the mitotic spindle.</p> Signup and view all the answers

<p>Microfilaments contribute to cytokinesis during cell division.</p> Signup and view all the answers

<p>Intermediate filaments provide structural support during cell division but are not directly involved in the process.</p> Signup and view all the answers

<p>Profilin and cofilin are actin-binding proteins (ABPs) that regulate the polymerization of microfilaments.</p> Signup and view all the answers

<p>Tropomyosin and troponin regulate actin's interaction with myosin.</p> Signup and view all the answers

<p>Motor proteins like dynein and kinesin facilitate intracellular transport in relation to microtubules.</p> Signup and view all the answers

<p>The assembly of intermediate filaments is less dynamic because phosphorylation and dephosphorylation of specific sites on intermediate filament proteins regulate their assembly and disassembly.</p> Signup and view all the answers

<p>Microfilaments are primarily composed of $actin$, and they play roles in contributing to cell shape, motility, and the dynamic process of cytokinesis during cell division in individual cells. In tissues, especially actin, microfilaments are essential for the structural integrity of epithelial cells, influencing resilience.</p> Signup and view all the answers

<p>Microtubules are formed by $tubulin$ proteins and serve crucial functions at the cellular level by organizing the mitotic spindle during cell division and facilitating intracellular transport. In tissues, microtubules contribute to the structural support of cells, help determine cell shape, and play essential roles in specialized tissues like muscle, where they are integral to sarcomere organization.</p> Signup and view all the answers

<p>Intermediate filaments are composed of various proteins such as $keratins$ and $vimentin$. They provide structural stability to individual cells and contribute to the integrity of tissues subjected to mechanical stress by adding resilience, especially in epithelial tissues, and supporting the structural integrity of neurons in neuronal tissues.</p> Signup and view all the answers

<p>The ECM is comprised of fibrous proteins like $collagen$ and $elastin$, as well as proteoglycans and glycoproteins. It serves as a scaffold, providing structural support to cells while influencing their behavior through signaling pathways.</p> Signup and view all the answers

<p>Integrins, cell surface receptors, play a crucial role in cell-ECM interactions by recognizing specific ECM molecules like fibronectin and collagen. These interactions trigger intracellular signaling that regulates various cellular activities.</p> Signup and view all the answers

<p>Focal adhesions, formed at sites of integrin-ECM attachment, serve as signaling hubs and activate pathways like the $Rho$ $GTPase$ pathway, which influences cytoskeletal dynamics and cell motility.</p> Signup and view all the answers

<p>Kinases activated by integrin engagement, such as $focal$ $adhesion$ $kinase$ ($FAK$) and $integrin$-$linked$ $kinase$ ($ILK$), phosphorylate downstream targets, influencing various cellular processes.</p> Signup and view all the answers

<p>Integrin-mediated interactions with the ECM dynamically regulate cell migration by influencing the organization of the cytoskeleton, resulting in changes in cell shape and the ability to navigate through the ECM. Integrins play a pivotal role in the dynamic regulation of cell adhesion and detachment during processes like cell migration.</p> Signup and view all the answers

<p>The ECM provides a microenvironment or niche for stem cells, influencing their fate decisions. Integrin-mediated signaling in the stem cell niche guides differentiation, with ECM molecules acting as signals that direct stem cells toward specific lineages.</p> Signup and view all the answers

<p>ECM signaling pathways impact gene expression through the activation of transcription factors like $nuclear$ $factor$ $kappa$ $B$ ($NF$-$\kappa$B$), influencing inflammatory responses and cell survival.</p> Signup and view all the answers

<p>Tissue formation involves coordinated cellular behaviours, including proliferation, migration, and differentiation, with cells actively secreting ECM components. Cell-ECM interactions play a pivotal role in maintaining tissue homeostasis during continuous remodelling and repair processes.</p> Signup and view all the answers

<p>The composition of the ECM affects whether stem cells differentiate into specific cell types or remain undifferentiated. Integrins play a crucial role in integrin-mediated signaling in the stem cell niche, guiding differentiation based on ECM signals.</p> Signup and view all the answers