biology

LAMP1

LAMP1 is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand LAMP1 rather than just read about it. In short: Lysosomal-associated membrane protein 1 (LAMP-1) also known as lysosome-associated membrane glycoprotein 1 and CD107a (Cluster of Differentiation 107a), is a protein that in humans is encoded by the LAMP1 gene. The human LAMP1 gene is located on the long arm (q) of chromosome 13 at region 3, band 4 (13q34).

Key takeaways

LAMP1 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect LAMP1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of LAMP1 from memory before moving on to harder problems.

Reference excerpt

Lysosomal-associated membrane protein 1 (LAMP-1) also known as lysosome-associated membrane glycoprotein 1 and CD107a (Cluster of Differentiation 107a), is a protein that in humans is encoded by the LAMP1 gene. The human LAMP1 gene is located on the long arm (q) of chromosome 13 at region 3, band 4 (13q34).

Lysosomal-associated membrane protein 1 is a glycoprotein from a family of Lysosome-associated membrane glycoproteins. The LAMP-1 glycoprotein is a type I transmembrane protein which is expressed at high or medium levels in at least 76 different normal tissue cell types. It resides primarily across lysosomal membranes, and functions to provide selectins with carbohydrate ligands. CD107a has also been shown to be a marker of degranulation on lymphocytes such as CD8+ and NK cells, and may also play a role in tumor cell differentiation and metastasis.

Structure Residing primarily across lysosomal membranes, these glycoproteins consist of a large, highly glycosylated end with N-linked carbon chains on the luminal side of the membrane, and a short C-terminal tail exposed to the cytoplasm. The extracytoplasmic region contains a hinge-like structure which can form disulphide bridges homologous to those observed in human immunoglobulin A. Other characteristics of the structure of the LAMP-1 glycoproteins include:

A polypeptide core of ~40 kDa 18 {N-glycosylation} sites to help with the addition of sugar chains Polylactosamine attachments which protect the glyocoprotein from degradation by lysosomal proteases Significant quantities of polylactosaminoglycan and sialic acid to traverse the trans-Golgi cisternae. poly-N-acetyllactosamine groups which are involved in interactions with selectin and other glycan-binding proteins

Function LAMP1 and LAMP2 glycoproteins comprise 50% of all lysosomal membrane proteins, and are thought to be responsible in part for maintaining lysosomal integrity, pH and catabolism. The expression of LAMP1 and LAMP2 glycoproteins are linked, as deficiencies in LAMP1 gene will lead to increased expression of LAMP2 glycoproteins. The two are therefore thought to share similar functions in vivo. However, this makes the determining the precise function of LAMP1 difficult, because while the LAMP1 deficient phenotype is little different than the wild type due to LAMP2 up regulation, the LAMP1/LAMP2 double deficient phenotype leads to embryonic lethality. Although the LAMP1 glycoproteins primarily reside across lysosomal membranes, in certain cases they can be expressed across the plasma membrane of the cell. Expression of LAMP1 at the cell surface can occur due to lysosomal fusion with the cell membrane. Cell surface expression of LAMP1 can serve as a ligand for selectins and help mediate cell-cell adhesion. Accordingly, cell surface expression of LAMP1 is seen in cells with migratory or invasive functions, such as cytotoxic T cells, platelets and macrophages. Cell surface expression of LAMP1 and LAMP2 is also often seen in cancer cells, particularly cancers with high metastatic potential, such as colon carcinoma and melanoma, and has been shown to correlate with their metastatic potential.

Role in cancer LAMP1 expression on the surface of tumor cells has been observed for a number of different cancer types, particularly in highly metastatic cancers such as pancreatic cancer, colon cancer and melanoma. The structure of LAMP1 correlates with differentiation and metastatic potential of tumor cells as it is thought to help mediate cell-cell adhesion and migration. Indeed, the adhesion of some cancer cells to the extracellular matrix is mediated by interactions between LAMP1 and LAMP2 and E-selectin and galectins, with the LAMPs serving as ligands for the cell-adhesion molecules. Cell membrane expression of LAMP-1 observed in the following cancer types:

Human fibrosarcoma, Colon adenocarcinoma, Melanoma, Pancreatic adenocarcinoma, and Astrocytoma.

Illustrations

Worked examples

Example 1 — a first encounter with LAMP1

Start with the simplest possible case. Write down what LAMP1 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to LAMP1 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about LAMP1 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of LAMP1

In research: LAMP1 appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses LAMP1 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: LAMP1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Clusters of differentiation, Genes on human chromosome 13, so understanding it makes those chapters shorter.
In everyday life: Look for LAMP1 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study LAMP1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LAMP1 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain LAMP1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LAMP1 in simple terms?

Why does LAMP1 matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study LAMP1?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on LAMP1.