Roles of the cytoskeleton and motor proteins in endocytic sorting.
After internalization, endocytic material is actively transported through the cytoplasm, predominantly by microtubule motor proteins. Microtubule-based endocytic transport facilitates sorting of endocytic contents, vesicle fusion and fission, delivery to lysosomes, cytosolic dispersal, as well as nuclear uptake and cytosolic egress of pathogens. Endosomes, like most organelles, move bidirectionally through the cytosol and regulate their cellular location by controlling the activity of motor proteins, and potentially by controlling microtubule and actin polymerization. Control of motor protein activity is manifest by increased microtubule "run lengths", and the binding of motor proteins to organelles can be regulated by motor protein receptors. A mechanistic understanding of how organelles control motor protein activity to allow for endocytic sorting presents an exciting avenue for future research.
Marion Bessin Liver Research Center and Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 517 Ullmann Building, 1300 Morris Park Avenue, Bronx, NY 10461, USA. john_w_murray@yahoo.com
John W
JW
Murray
Allan W
AW
Wolkoff
D000818:Animals; D001692:Biological Transport; D003599:Cytoskeleton / Q000378:metabolism* / Q000502:physiology; D004705:Endocytosis / Q000502:physiology*; D011992:Endosomes / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D020409:Molecular Motor Proteins / Q000378:metabolism* / Q000502:physiology; D014780:Viruses / Q000378:metabolism
D020409:Molecular Motor Proteins