lecture13C Lipid Modifications and Membrane Localization

These flashcards cover key terms and definitions related to lipid modifications and membrane localization as discussed in the lecture.

Prenylation

A type of lipid modification involving a thioether linkage to Cys near the protein C-terminus, typically using Farnesyl (C15) or Geranylgeraniol (C20).

Fatty Acylation

Lipid modification that involves attaching fatty acid chains, such as Myristate linked to GLY on the N-terminus and Palmitate usually linked via thioester to a CYS.

Glycosyl-Phosphatidyl-Inositol (GPI)-Linked Protein

A type of protein that is covalently attached to the membrane via a phosphatidylinositol group, often found on the luminal side.

Caveolin

A protein that forms dimers, is multi-palmitoylated, binds cholesterol, and promotes membrane curvature.

Caveola

Small membrane invaginations enriched in cholesterol, sphingolipids, and GPI-anchored proteins.

Lipid Rafts

Microdomains in the plasma membrane that are rich in cholesterol and sphingolipids.

Thioester Linkages

Chemical bonds that can be cleaved, releasing an anchored protein from the membrane.

Outer Leaflet

The external layer of the plasma membrane where GPI-anchored proteins are commonly found.

Cytoskeleton

The intracellular filament system that controls cell morphology, movement, and intracellular transport.

Actin Filaments

Filamentous proteins that are important components of the cytoskeleton involved in maintaining cell shape.

Spectrin

Protein that forms long filaments on the cytosolic side of the plasma membrane, anchoring to specific integral membrane proteins.

Erythrocyte

A red blood cell specialized in oxygen transport, characterized by its biconcave shape.

Filamentous Proteins

Protein structures that provide shape and support within the cytoskeleton.

Fluid Mosaic Model

A model that describes the plasma membrane as a dynamic structure with various proteins and lipids capable of movement.

Membrane Curvature

The bending of the plasma membrane, which can be influenced by proteins such as caveolin.

Cytoskeletal Fencing

Restrictions on lateral diffusion of proteins within the membrane due to the interactions with the cytoskeleton.

Integral Membrane Proteins

Proteins that span the membrane and can interact with lipid rafts and the cytoskeleton.

Microvilli

Small projections on the cell surface that increase surface area for absorption or secretion.

Intermediate Filaments

Components of the cytoskeleton that provide structural support and stability to cells.

Cholesterol

A lipid that is a part of the plasma membrane structure and plays a role in membrane fluidity.

Membrane Crowding

The phenomenon in which a high density of proteins in the membrane can affect protein interactions and function.

Filament System

Includes actin, microtubules, and intermediate filaments as part of the cytoskeletal structure.

Thrombocyte

A platelet, a specialized cell involved in blood clotting.

Leukocyte

A white blood cell involved in immune response.

Palmitoylation

A specific type of fatty acylation that typically involves the attachment of palmitate to cysteine residues.