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.
Sanderson
C M
CM
Department of Microbiology and Immunology, Jonsson Comprehensive Cancer Center, UCLA School of Medicine 90024-1747.
McQueen
N L
NL
Nayak
D P
DP
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