title: Leishmania donovani infection enhances lateral mobility of macrophage membrane protein which is reversed by liposomal cholesterol.
abstract: BACKGROUND
  The protozoan parasite Leishmania donovani (LD) reduces cellular cholesterol of the host possibly for its own benefit. Cholesterol is mostly present in the specialized compartment of the plasma membrane. The relation between mobility of membrane proteins and cholesterol depletion from membrane continues to be an important issue. The notion that leishmania infection alters the mobility of membrane proteins stems from our previous study where we showed that the distance between subunits of IFNγ receptor (R1 and R2) on the cell surface of LD infected cell is increased, but is restored to normal by liposomal cholesterol treatment.
  
  
  RESULTS
  We determined the lateral mobility of a membrane protein in normal, LD infected and liposome treated LD infected cells using GFP-tagged PLCδ1 as a probe. The mobility of PLCδ1 was computationally analyzed from the time lapse experiment using boundary distance plot and radial profile movement. Our results showed that the lateral mobility of the membrane protein, which is increased in infection, is restored to normal upon liposomal cholesterol treatment. The results of FRAP experiment lent further credence to the above notion. The membrane proteins are intimately linked with cellular actin and alteration of cellular actin may influence lateral mobility. We found that F-actin is decreased in infection but is restored to normal upon liposomal cholesterol treatment as evident from phalloidin staining and also from biochemical analysis by immunoblotting.
  
  
  CONCLUSIONS
  To our knowledge this is the first direct demonstration that LD parasites during their intracellular life cycle increases lateral mobility of membrane proteins and decreases F-actin level in infected macrophages. Such defects may contribute to ineffective intracellular signaling and other cellular functions.
authors.affiliation: Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
authors.forename: Moumita
authors.initials: M
authors.lastname: Ghosh
authors.affiliation: Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
authors.forename: Koushik
authors.initials: K
authors.lastname: Roy
authors.affiliation: Department of Biotechnology, University of Calcutta, Kolkata, India.
authors.forename: Dipanwita
authors.initials: D
authors.lastname: Das Mukherjee
authors.affiliation: Department of Biotechnology, University of Calcutta, Kolkata, India.
authors.forename: Gopal
authors.initials: G
authors.lastname: Chakrabarti
authors.affiliation: Departmentof Biostatistics and Bioinformatics, Duke University, Durham, North Carolina, United States of America.
authors.forename: Kingshuk
authors.initials: K
authors.lastname: Roy Choudhury
authors.affiliation: Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
authors.forename: Syamal
authors.initials: S
authors.lastname: Roy
mesh_terms: D000818:Animals; D002460:Cell Line; D002784:Cholesterol / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D007893:Leishmania donovani / Q000737:chemistry / Q000378:metabolism*; D007898:Leishmaniasis, Visceral / Q000469:parasitology / Q000503:physiopathology; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D008264:Macrophages / Q000737:chemistry / Q000166:cytology / Q000378:metabolism* / Q000469:parasitology; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice
chemical_list: D008081:Liposomes; D008565:Membrane Proteins; D002784:Cholesterol