Table 1.

A selected number of NCAP interacting proteins involved in immune response and their associated functions

No.	Protein	Functions	Type of interaction	References
1	IMPDH2	Regulates NF‐kB activation and supports SARS‐CoV infection	Non‐stress	[75]
2	TRIM56	Positive regulator of innate immune response.	Non‐stress	[78]
3	ANXA1	Plays a vital role in TLR activation, leading to an augmentation in the type 1 IFN antiviral cytokine response; Promotes RIG‐I‐dependent signalling and apoptosis via regulation of the IRF3–IFNAR–STAT1–IFIT1 pathway in A549 lung epithelial cells.	Non‐stress	[80, 81]
4	AP3B1	Required for the production of pro‐inflammatory cytokines in response to viral nucleic acids; significantly enriched in COVID‐19 patients experiencing severe cytokine storms; Crucial for the trafficking of TLR9 to specific endosomal compartments for the induction of type I interferon.	Non‐stress	[82, 83, 84]
5	ASCC3	Inhibits IFN‐signalling to dampen antiviral innate immunity.	Non‐stress	[92]
6	BAIAP2L1	Involved in MAVS degradation, leading to downregulation of antiviral responses.	Non‐stress	[93]
7	HSP90B1	Amplifies innate and adaptive immune responses via interaction with TLR2 and TLR4 ligands.	Non‐stress	[85]
8	PPP1CA	Dephosphorylates RNA sensors, RIG‐I (DDX58) and MDA5 (IFIH1), to induce antiviral IFN‐b production.	Non‐stress	[86]
9	PURA	Regulates several human viruses that replicate in the central nervous system (CNS), including human immunodeficiency virus type I (HIV‐1) and JC virus (JCV).	Non‐stress	[107]
10	RICTOR	Reduces TLR4‐mediated inflammation by regulating the cellular localization of FOXO1.	Non‐stress	[108]
11	RPL19	Facilitates viral multiplication in cells that express TLR3 in endosomes while inhibiting viral multiplication in cells bearing TLR3 on their cell membrane; Interacts with MIF and attenuates its pro‐inflammatory function.	Non‐stress	[109, 110]
12	YBX1	Functions as a porter to lead influenza virus ribonucleoprotein complexes to microtubules; Supports the early and late stages of HIV replication.	Non‐stress	[94, 95]
13	YY1	Negatively regulates TLR3‐induced expression of IFN‐b and acts downstream of TLR3 to limit the level and duration of antiviral response.	Non‐stress	[87]
14	VCP	Involved in the maturation of virus‐loaded endosomes	Stress‐enhanced	[76]
15	EFTUD2	Novel innate immune regulator that restricts Hepatitis C virus infection through an RIG‐I/MDA5‐mediated, JAK‐STAT‐independent pathway.	Stress‐enhanced	[88]
16	PCBP1	Critical in regulating MAVS degradation for both fine‐tuning antiviral immunity and preventing inflammation.	Stress‐enhanced	[89]
17	TRIM21	Negatively regulates the innate immune response to intracellular double‐stranded DNA; Interacts with MAVS to positively regulate innate immunity	Stress‐enhanced	[111, 112]
18	EIF2AK2 (PKR)	An essential mediator of the antiviral and anti‐proliferative actions of interferon (IFN); Recruited to stress granules by G3BP1 to promote innate immune responses at both transcriptional and translational levels.	Stress‐independent	[23, 113]
19	G3BP1	Inhibits RNA virus replication by positively regulating RIG‐I‐mediated cellular antiviral response; Recruits protein kinase R to promote multiple innate immune antiviral responses.	Stress‐independent	[23, 114, 115]
20	HSPA1A	Highly upregulated at the maternal–fetal interface during maternal COVID‐19; Mediates protective antiviral immunity in response to measles virus (MeV) brain infection.	Stress‐independent	[90, 91]
21	LGALS1	Stimulates monocyte migration via the p44/42 MAP kinase pathway.	Stress‐independent	[116]
22	NAMPT	Activates Toll‐Like Receptor 4 to Induce NFκB signalling and inflammatory lung injury.	Stress‐independent	[117]
23	PRKRA	Activated by double‐stranded RNA which mediates the effects of interferon in response to viral infection.	Stress‐independent	[118]
24	SQSTM1	Key intracellular target of innate defence regulator‐1 (IDR‐1).	Stress‐independent	[119]
25	XRCC5	Vaccinia virus protein C16 influences the immune response by binding to the XRCC6/XRCC5 (Ku70/80) complex, thus, blocking PRKDC‐dependent DNA sensing in fibroblasts.	Stress‐independent	[120]
26	ADAR	A negative regulator of type I interferon‐mediated signalling pathway.	Stress‐dependent	[96]
27	PCBP2	A negative regulator in MAVS‐mediated antiviral signalling; Synergizes with PCBP1 in MAVS inhibition.	Stress‐dependent	[89, 97]