Which one of the following proteins is NOT related to extracellular matrix?
Lamin
Proteins and the Extracellular Matrix
This question asks us to identify which of the listed proteins is NOT related to the extracellular matrix (ECM). The extracellular matrix is a complex network of macromolecules secreted by cells that provides structural and biochemical support to surrounding cells. It plays a crucial role in cell adhesion, migration, proliferation, and differentiation.
Understanding Extracellular Matrix Components
Let's look at each option:
- Cadherin: Cadherins are a class of transmembrane proteins that mediate calcium-dependent cell-cell adhesion. While they are involved in linking cells to form tissues and often interact with the cytoskeleton, they are primarily cell-surface adhesion molecules, not typical components of the extracellular matrix itself.
- Vitronectin: Vitronectin is an adhesive glycoprotein found in the extracellular matrix and blood. It is a well-known component of the ECM, involved in cell adhesion, spreading, and migration, often binding to integrin receptors on the cell surface.
- Lamin: Lamins are intermediate filament proteins that form a fibrous layer called the nuclear lamina, located just inside the inner nuclear membrane of eukaryotic cells. The nuclear lamina provides structural support to the nucleus and is involved in chromatin organization and gene regulation. Lamins are localized to the nucleus and are therefore NOT related to the extracellular matrix, which is outside the cell.
- Selectin: Selectins are a family of cell surface carbohydrate-binding proteins (lectins) that play a crucial role in cell adhesion, particularly in the immune system (e.g., leukocyte rolling along endothelial cells). Like cadherins, they are cell-surface proteins involved in cell-cell interactions, not primary components of the extracellular matrix.
Identifying the Non-ECM Protein
Based on the functions and locations of these proteins:
- Vitronectin is an extracellular matrix protein.
- Cadherins and Selectins are cell surface proteins involved in cell adhesion in the extracellular space, interacting with other cells or sometimes the ECM, but they are not considered core components of the ECM itself in the same way Vitronectin is.
- Lamin is a nuclear protein, forming the nuclear lamina inside the nucleus.
Therefore, Lamin is the protein that is definitively NOT related to the extracellular matrix, as its function and location are entirely intracellular and specifically within the nucleus.
Conclusion
The protein among the options that is NOT related to the extracellular matrix is Lamin.
Important Questions from Cellular communication
In a neuron, proteins and membranes are primarily synthesized in the cell body. These materials must be transported down the axon to the synaptic region using microtubules in an anterograde fashion. Such axonal transport is directed by
Acetylcholine is a potent neurotransmitter, which is released from the neurons. After release they diffuse across the synaptic cleft and combine with nicotinic acetylcholine receptor molecules in the membrane of the postsynaptic cell. The interaction of acetylcholine with the nicotinic acetylcholine receptor produces large transient increase in the permeability of the membrane to specialized ions resulting in signal transduction for nerve impulse. Acetylcholine receptor is a
Column X represents the type of junctions and column Y represents the proteins associated with the junctions.
Column X
Column Y
A.
Anchoring junction
i.
Claudins
B.
Occluding junction
ii.
Delta-Notch
C.
Channel-forming junction
iii.
Desmoglein
D.
Signal-relaying junction
iv.
Connexin
Which one of the following options is a correct match between terms of Columns X and Y?
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A. Some bacteria express a protein called invasin that is recognized by host-cell β1 integrins.
B. Actin polymerization along with assembly of clathrin coat results in the internalization of bacteria by zipper mechanism.
C. Some bacteria, including Salmonella enterica, use trigger mechanism to inject a set of effector molecules in the cytosol through type III secretion system.
D. Some bacteria attach to host cell surface receptors inducing local elevation of Ca2+ in cell cytosol, leading to the fusion of lysosomes with bacteria containing plasma membrane vesicles.
Which one of the following represents the combination of correct mechanisms for invading non-phagocytic cells?
In C. elegans, PAR proteins segregate at the cell cortex in the zygote to establish cell polarity. This is dependent on the regulation of the cortical actin cytoskeleton by RhoA. An investigator sought to directly inhibit actin polymerization to analyze the impact of this inhibition on PAR protein localization. Which one of the following chemicals would be the most suitable?
