Restricted lateral diffusion of PH-20, a PI-anchored sperm membrane protein.
The rate of lateral diffusion of integral membrane proteins is constrained in cells, but the constraining factors for most membrane proteins have not been defined. PH-20, a sperm surface protein involved in sperm-egg adhesion, was shown to be anchored in the plasma membrane by attachment to the lipid phosphatidylinositol and to have a diffusion rate that is highly restricted on testicular sperm, being more than a thousand times slower than lipid diffusion. These results support the hypothesis that lateral mobility of a membrane protein can be regulated exclusively by interactions of its ectodomain.
Phelps
B M
BM
Department of Physiology, University of Connecticut Health Center, Farmington 06032.
Primakoff
P
P
Koppel
D E
DE
Low
M G
MG
Myles
D G
DG
D000818:Animals; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D002451:Cell Compartmentation; D002462:Cell Membrane / Q000502:physiology; D004058:Diffusion; D006168:Guinea Pigs; D008297:Male; D008560:Membrane Fluidity; D008565:Membrane Proteins / Q000502:physiology*; D010716:Phosphatidylinositols / Q000502:physiology*; D013079:Sperm Maturation; D013094:Spermatozoa / Q000502:physiology*; D013737:Testis / Q000502:physiology
D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D008565:Membrane Proteins; D010716:Phosphatidylinositols