I do not know for what reason this paper would be retracted. It is describing the biochemistry of SARS-CoV-2 virion/host lipid membrane fusion. Its main finding is that the ACE2 receptor is not absolutely required for the SARS-CoV-2 virion to fuse with a lipid membrane, although it is still necessary to tether the virus to the membrane for this to occur.
Membrane fusion occurs between lipid bilayers. The role of the proteins is to place those bilayers in close proximity so that fusion can take place. The implication of this paper is that SARS-CoV-2 virions can potentially bind to cells lacking the ACE2 receptor, resulting in a greater range of tissue tropism. This, in turn, increases the potential for tissue damage during Covid infection.
Both the scientific content and the experimental methodology of this paper are sound.
There are many reasons that scientific papers are retracted. One common reason is that they are repeats of other published papers. Other reasons can be that the data is questionable, the experiments are unrepeatable, or even that there is evidence of fraud. Sometimes antivax/charlatans will write a pseudopaper intended to promote misinformation and actually succeed in getting it published.
Don’t focus on my reluctance to copy/paste/format the entire paper.
I believe it’s sound as well, especially the more of it I digest.