RED CELL MEMBRANE

CLINICAL LAB SCIENCES 3RD YR 5TH SEMESTER

CELL MEMBRANE OF RBC

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RBC CELL MEMBRANE:

CONSIST OF:

PROTEIN 50% PHOSPHOLIPID 20% CHOLESTROL MOLECULES 20% CARBOHYDRATE 10%

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THREE BASIC COMPONENTS OF RBC

CELL MEMBRANE

Lipid bilayer. Integral membrane protein. A membrane cytoskeleton.

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1.LIPID BILAYER:

Consist of: Phospholipid. Cholestrol. Glycolipid. Integral protein. Peripheral protein.

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2.MEMBRANE PROTEINS:

Peripheral protein:

Trophomyosin Spectrin Actin Protein 4.1 Ankyrin Protein 4.2

Integral protein:

Glycophorin Band 3 protein (chloride shift)

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Names Definition Function

Peripheral protein

1. Spectrin

2. Actin

3. Ankyrin

4. Protein 4.1

5. Protein 4.2

6. Trophomyosin

cytoskeletal protein that lines the intracellular side of the plasma membrane Abundant protein in cell membrane

are a family of adaptor protein

is a major structural element.

is an ATP-binding protein

Heterodimeric protein

Responsible for biconcave shape of RBC

participates in more protein-protein interactions

Interacts with band 3 protein and spectrin to achieve linkage between bilayer andskeleton.

Stabilises actin-spectrin interactions.regulate the association of protein 3 with ankyrin.Stabilizing the actin filaments.

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Names Definition Function

Integral protein

1. Glycophorin

2. Band 3 protein

Sialic acid rich glycoproteins

anion exchanger 1

imparts a negative charge to the cell,reducing interaction with other cells/endotheliumExchanges bicarbonate for chloride (chlorine shift).

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3.CYTOSKELETON:

1. Formed by structural protein

2. Basic unit : hexagonal lattice with 6 spectrin molecules.

3. Tail end: tetramers linked to actin and protein 4.1. 4. Head end: ß spectrin linked to ankyrin

PLANE OF DESIGN:

1. Vertical interaction: • Stabilise the lipid bilayer membrane.

2. Horizontal interaction: • Maintain biconcave shape of RBC

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DEFECTS IN RBC CELL MEMBRANE:

1.Hereditary spherocytosis:

• Hereditary hemolytic disorder. (most commom)• Mutation in membrane protein (spherical rbc)

• Clinical features: anemia. jaundice. fatigue. splenomegaly.

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2. Elliptocytosis:

• Rare hereditary disorder.• also known as ovalocytosis.• Oval shape rbc.• It is a hemolytic anemia (severe cases)• Treatment: splenectomy

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