Which of the following is/are extra-cellular matrix protein(s)?
- (A)
Myosin
- (B)
Fibronectin
- (C)
Lamin
- (D)
Collagen
Which of the following is/are extra-cellular matrix protein(s)?
Myosin
Fibronectin
Lamin
Collagen
ANSWER
The extra-cellular matrix proteins are Fibronectin (B) and Collagen (D).
Official answer: B, DSource: Official answer key, GATE 2026 BT (IIT Guwahati)
Myosin is a motor protein that operates in the cytoplasm, moving along actin filaments to generate force; it is never secreted into the extracellular space, so it is not an ECM protein.
Fibronectin is a glycoprotein secreted into the extracellular matrix, where it links cells to collagen and other matrix components via integrin receptors — a classic ECM protein.
Lamin is a nuclear intermediate filament protein that forms the nuclear lamina lining the inner nuclear membrane; it is strictly intracellular and structurally supports the nucleus, not the ECM.
Collagen is the principal fibrous structural protein of the extracellular matrix, giving connective tissue its tensile strength — a classic ECM protein.
Therefore the extracellular matrix proteins among the options are Fibronectin (B) and Collagen (D).
KEY IDEA
The extracellular matrix (ECM) is built mainly of structural fibrous proteins (like collagen) and adhesive glycoproteins (like fibronectin) that are secreted by cells into the space outside them; motor proteins (myosin) and nuclear lamina proteins (lamins) are intracellular, not ECM components.
WATCH OUT FOR
Confusing "structural protein" in general with "extracellular matrix protein" specifically — students sometimes mark Lamin because it is also a structural (intermediate filament) protein, forgetting that lamins line the INNER nuclear membrane and are strictly intracellular, not secreted into the ECM.
From the GATE 2026 BT paper. Every question of this paper · Download the full paper · All 15 Cell biology questions, with notes