Sendai virus assembly: M protein binds to viral glycoproteins in transit through the secretory pathway.
We have examined the relative ability of Sendai virus M (matrix) protein to associate with membranes containing viral glycoproteins at three distinct stages of the exocytic pathway prior to cell surface appearance. By the use of selective low-temperature incubations or the ionophore monensin, the transport of newly synthesized viral glycoproteins was restricted to either the pre-Golgi intermediate compartment (by incubation at 15 degrees C), the medial Golgi (in the presence of monensin), or the trans-Golgi network (by incubation at 20 degrees C). All three of these treatments resulted in a marked accumulation of the M protein on perinuclear Golgi-like membranes which in each case directly reflected the distribution of the viral F protein. Subsequent redistribution of the F protein to the plasma membrane by removal of the low-temperature (20 degrees C) block resulted in a concomitant redistribution of the M protein, thus implying association of the two components during intracellular transit. The extent of M protein-glycoprotein association was further examined by cell fractionation studies performed under each of the three restrictive conditions. Following equilibrium sedimentation of membranes derived from monensin-treated cells, approximately 40% of the recovered M protein was found to cofractionate with membranes containing the viral glycoproteins. Also, by flotation analyses, a comparable subpopulation of M protein was found to be membrane associated whether viral glycoproteins were restricted to the trans-Golgi network, the medial Golgi, or the pre-Golgi intermediate compartment. Additionally, transient expression of M protein alone from cloned cDNA showed that neither membrane association nor Golgi localization occurs in the absence of Sendai virus glycoproteins.
Department of Microbiology and Immunology, Jonsson Comprehensive Cancer Center, UCLA School of Medicine 90024-1747.
C M
CM
Sanderson
N L
NL
McQueen
D P
DP
Nayak
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002451:Cell Compartmentation; D002478:Cells, Cultured; D002642:Chick Embryo; D005089:Exocytosis / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000502:physiology; D008985:Monensin / Q000494:pharmacology; D010222:Parainfluenza Virus 1, Human / Q000235:genetics / Q000254:growth & development*; D011994:Recombinant Proteins / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics / Q000254:growth & development; D014760:Viral Fusion Proteins / Q000378:metabolism*; D014763:Viral Matrix Proteins / Q000302:isolation & purification / Q000378:metabolism*
C075739:F protein, parainfluenza virus 1; D011994:Recombinant Proteins; D014760:Viral Fusion Proteins; D014763:Viral Matrix Proteins; D008985:Monensin