Name: coronavirus spike proteins and cell entry
Uploaded: 2026-05-20T14:16:22.219Z
Duration: 1 min 29 s
Channel: JoVE

Coronaviruses are enveloped RNA viruses. They cause mild to severe respiratory illness and spread through respiratory droplets.During infection, the virus binds to host cell surface receptors, fuses its membrane with the host cell membrane, and releases its RNA.Once inside, cytoplasmic ribosomes translate the viral RNA into polyproteins that contain proteases.These proteases cleave the polyproteins into different nonstructural proteins.Some nonstructural proteins cause conformational change in the endoplasmic reticulum, forming double-membrane vesicles.Other nonstructural proteins form a replication&#x2013;transcription complex that attaches to these vesicles. Here, viral RNA replicates, and shorter mRNAs are produced that encode viral proteins.Viral envelope proteins are transported to the ER&#x2013;Golgi intermediate compartment.The replicated viral RNA binds to nucleocapsid proteins and moves to the ER&#x2013;Golgi intermediate compartment, where virion assembly begins.The newly formed virions travel in vesicles and exit through exocytosis to infect other cells.

coronavirus

Coronavirus

Coronaviruses, including the severe acute respiratory syndrome coronavirus (SARS-CoV), are enveloped viruses characterized by their single-stranded, positive-sense RNA genome and helical nucleocapsid structure. The hallmark of these viruses is their club-shaped spike (S) glycoproteins that protrude from the viral envelope, facilitating attachment to host cells. Typically, coronaviruses infect the upper respiratory tract, often causing mild or asymptomatic disease. However, certain strains like SARS-CoV can cause severe respiratory syndromes, particularly in high-risk populations.Viral Entry and TranslationSARS-CoV initiates infection through the binding of its spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor on host cells. This interaction prompts receptor-mediated endocytosis or direct fusion of the viral and cellular membranes, followed by release of the viral RNA genome into the cytoplasm. The genome functions as mRNA and is immediately translated by host ribosomes into two large polyproteins: pp1a and pp1ab. These polyproteins are then processed by viral proteases into non-structural proteins (nsps), which assemble into the replication-transcription complex (RTC).Replication and TranscriptionThe RTC localizes to modified intracellular compartments, notably double-membrane vesicles (DMVs) and convoluted membranes derived from the endoplasmic reticulum. These organelles provide a protected niche for RNA synthesis, shielding viral replication from host defenses. The RTC mediates both the replication of the full-length genome and the synthesis of a nested set of subgenomic mRNAs encoding structural and accessory proteins.Assembly and ReleaseFollowing translation, structural proteins such as spike (S), membrane (M), and envelope (E) are directed to the endoplasmic reticulum (ER) and then to the ER-Golgi intermediate compartment (ERGIC). Here, genomic RNA is encapsidated by the nucleocapsid (N) protein, and virion assembly occurs. Mature virions bud into vesicles and are transported to the cell surface, where they are released via exocytosis.Clinical ManifestationsWhile many infections are mild, SARS-CoV can provoke serious clinical outcomes, including high fever, persistent cough, pneumonia, and systemic involvement such as multi-organ failure, particularly in individuals with comorbidities or weakened immune systems.

https://cloudfront.jove.com/files/ftp_upload/40846/40846_article_thumb_40846.jpg

Education

JoVE Core

Microbiology

Unit

Viral Infections

KEY TERMS AND CONCEPTS

coronavirus spike proteins and cell entry

Coronaviruses are enveloped viruses with a single-stranded, positive-sense RNA genome and a helical nucleocapsid. Their club-shaped spike glycoproteins stand out on the viral envelope and help the virus attach to host cells. Most coronaviruses infect the upper respiratory tract and often cause mild or no symptoms. Some strains, including SARS-CoV, can cause severe respiratory disease, especially in people at higher risk.

SARS-CoV starts infection when its spike protein binds to the angiotensin-converting enzyme 2, or ACE2, receptor on a host cell. This binding can lead to receptor-mediated endocytosis or direct fusion of the viral and cell membranes. After entry, the viral RNA genome is released into the cytoplasm. The genome then acts like mRNA and is immediately translated by host ribosomes into two large polyproteins, pp1a and pp1ab.

Viral proteases cut these polyproteins into non-structural proteins, or nsps. These proteins form the replication-transcription complex, called the RTC. The RTC moves to modified intracellular compartments, including double-membrane vesicles and convoluted membranes made from the endoplasmic reticulum. These compartments give the virus a protected place for RNA synthesis and help shield it from host defenses.

The RTC carries out both genome replication and the production of a nested set of subgenomic mRNAs. These mRNAs encode structural proteins and accessory proteins. Structural proteins such as spike, membrane, and envelope are sent to the endoplasmic reticulum and then to the ER-Golgi intermediate compartment, or ERGIC. There, genomic RNA is packaged by the nucleocapsid, or N, protein, and new virions are assembled.

Mature virions bud into vesicles and move to the cell surface. They are then released by exocytosis. While many coronavirus infections are mild, SARS-CoV can cause high fever, a persistent cough, pneumonia, and even multi-organ failure. These severe outcomes are more likely in people with comorbidities or weakened immune systems.

Coronavirus Spike Proteins and Cell Entry

coronavirus-spike-proteins-and-cell-entry

smallpox

Smallpox Signs, Spread, and Prevention

Smallpox is a severe contagious disease caused by the Variola major virus. This virus is a double-stranded DNA member of the Poxviridae family. It spreads mainly through inhaling virus-laden droplets or through direct contact with infectious scabs. After exposure, the incubation period is usually about seven days. It can range from 7 to 17 days, depending on the amount of virus and host factors. The first symptoms appear suddenly and include high fever, malaise, headache, and myalgia, which...

herpes

HSV-1: Latency, Diagnosis, and Treatment

Herpes simplex virus type 1, or HSV-1, is a widespread double-stranded DNA virus that causes orolabial lesions. It is an enveloped virus in the Herpesviridae family. After it enters a host cell, its DNA travels to the nucleus, where immediate-early, early, and late genes are turned on in order. This gene sequence supports viral DNA copying, structural protein production, and new virion assembly. HSV-1 first infects epithelial cells, then it can become latent in sensory neurons of the...

chickenpox

Chickenpox Spread, Rash, and Latency

Chickenpox is a highly contagious disease caused by the varicella-zoster virus (VZV). VZV is a double-stranded DNA virus in the Herpesviridae family. The infection spreads through respiratory droplets or by direct contact with fluid from skin blisters. After exposure, the virus usually incubates for 10 to 21 days. During this time, it replicates and moves through the body in stages. Chickenpox is often mild and self-limiting in children, but it can cause serious complications in neonates,...

viral meningitis

Viral Meningitis: Signs, Testing, and Care

Viral meningitis affects the membranes around the brain and spinal cord and is the most common form of meningitis. It is also called aseptic meningitis because bacteria are not involved. In many cases, it is milder than bacterial meningitis, but it can still cause fever, headache, stiff neck, drowsiness, nausea, photophobia, and vomiting. Enteroviruses are common causes of viral meningitis. These include coxsackie A and B viruses and echoviruses. They belong to the Enterovirus genus in the...

poliomyelitis

Poliovirus Spread and Prevention

Poliovirus spread and prevention are key to understanding poliomyelitis. Poliomyelitis is caused by poliovirus, a small, non-enveloped, positive-sense RNA virus in the Picornaviridae family and Enterovirus genus. The virus spreads mainly by the fecal-oral route, often through contaminated water or food. After infection, poliovirus first replicates in the oropharynx and intestinal mucosa. It often multiplies in lymphoid tissues such as the tonsils, Peyer’s patches, and regional lymph nodes. A...

rabies

How Rabies Spreads in the Body

Rabies is a lethal zoonotic disease caused by a single-stranded, negative-sense RNA virus from the Lyssavirus genus in the Rhabdoviridae family. It usually spreads to humans through bites or saliva-contaminated scratches from infected mammals such as dogs, bats, raccoons, or foxes. The virus can also spread when infectious saliva contacts broken skin or intact mucous membranes, including the conjunctiva. After a bite or scratch, rabies first enters local muscle cells by receptor-mediated...

arboviral encephalitis

West Nile Virus and Brain Infection

West Nile virus can cause brain inflammation when it reaches the central nervous system. This arboviral infection is spread by mosquitoes, especially in a cycle that involves birds as amplifying hosts and mosquitoes as vectors. Humans and other mammals are incidental dead-end hosts. Most human infections never become severe, but some progress to neuroinvasive disease. West Nile virus, or WNV, is an enveloped, positive-sense, single-stranded RNA virus in the Flaviviridae family. Infection...

yellow fever

Yellow Fever: Mosquito Spread and Liver Damage

Yellow fever is a viral hemorrhagic disease that spreads through mosquito bites and can damage the liver. The yellow fever virus, or YFV, belongs to the Flaviviridae family. It is transmitted mainly by Aedes and Haemagogus mosquitoes in tropical and subtropical regions of Africa and South America. After a mosquito bite, the virus first infects immune cells in the skin, including dendritic cells and macrophages. These cells move to the lymph nodes, where the virus multiplies further. The...

cytomegalovirus disease

CMV Transmission and Reactivation

Cytomegalovirus (CMV) is a human double-stranded DNA virus in the Herpesviridae family. CMV disease can be mild or silent in many healthy people, but it can cause serious illness in newborns and in people with weakened immune systems. It is also a major cause of congenital viral infection in the United States and a common problem in solid organ and hematopoietic stem cell transplant recipients. CMV spreads through bodily fluids, sexual contact, organ transplantation, blood transfusions, and...

influenza

How Influenza Spreads and Replicates

Influenza is a highly contagious viral disease of the respiratory tract. It causes seasonal epidemics around the world. Influenza A is the most common type linked to large outbreaks. It is classified by two surface glycoproteins, hemagglutinin, or H, and neuraminidase, or N, as in H1N1. These glycoproteins help the virus infect cells, spread between people, and avoid immune detection. Influenza spreads mainly through respiratory droplets and contaminated surfaces. People in high-risk groups...

Coronaviruses are enveloped viruses with a single-stranded, positive-sense RNA genome and a helical nucleocapsid. Their club-shaped spike glycoproteins stand out on the viral envelope and help the virus attach to host cells. Most coronaviruses infect the upper respiratory tract and often cause mild or no symptoms. Some strains, including SARS-CoV, can cause severe respiratory disease, especially in people at higher risk. SARS-CoV starts infection when its spike protein binds to the...

respiratory syncytial virus disease

RSV Infection and Lung Cell Entry

Respiratory syncytial virus (RSV) is a common respiratory virus that can infect the lungs and airways. It mainly causes illness in infants and young children, but it can also seriously affect older adults and people with weak immune systems. RSV belongs to the Pneumoviridae family and is a negative-sense, single-stranded RNA virus in the Pneumovirus genus. RSV has a major global health impact. It causes millions of infections each year and leads to hospitalizations and deaths, especially in...

hepatitis

Hepatitis Viruses and Liver Inflammation

Hepatitis is inflammation of the liver. It is most often caused by hepatotropic viruses, which are viruses that infect the liver. Alcohol and some drugs can also cause it. Hepatitis A virus, or HAV, is a non-enveloped RNA virus in the Picornaviridae family. It usually spreads through the fecal-oral route, often from contaminated food or water. After it is swallowed, HAV can enter the bloodstream through the oropharynx or intestinal epithelium and then reach the liver. HAV infects hepatocytes,...

genital herpes

Genital Herpes: Diagnosis and Recurrence

Genital herpes is a sexually transmitted infection caused mainly by herpes simplex virus type 2 (HSV-2). Herpes simplex virus type 1 (HSV-1) is also increasingly linked to genital infections, especially in younger people. The virus spreads mainly through sexual contact. A major challenge is asymptomatic viral shedding, which means people can pass the virus on even when they have no symptoms. HSV-2 is common worldwide. The World Health Organization estimates that about 13% of people ages 15 to...

key terms and concepts

Learn how coronavirus spike proteins bind ACE2, enter host cells, copy viral RNA, assemble new virions, and can cause severe respiratory disease.

Coronavirus Spike Proteins and Cell Entry | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Coronavirus Spike Proteins and Cell Entry

Description

Transcript

Tags