Amyloid-beta (Aβ) deposition in the brain, is closely linked to development of Alzheimer’s disease (AD). Unfortunately, therapies specifically targeting Aβ deposition have failed to reach their primary clinical endpoints, emphasizing the need to broaden the search strategy for identification of alternative therapeutic targets/mechanisms. Transglutaminase (TG2) catalyses posttranslational modifications, is present in characteristic AD lesions and has AD-associated proteins, including Aβ, tau and apolipoprotein E. However, an unbiased overview of TG2 interactors (TG2 interactome) and the cellular pathways of which these interactors are part in control and AD brain is lacking. Here, anticipating future studies in AD brain, we aimed to identify these interactors and their pathways using a crossbred of the AD-mimicking APP23 mouse model with wildtype and TG2-/- mice. We found that absence of TG2 had no (statistically) significant effect on Aβ pathology, soluble brain levels of Aβ1-40, Aβ1-42, and mRNA levels of TG2 family members compared to APP23 mice. Quantitative proteomics and network analysis revealed a large cluster of TG2 interactors with synaptic transmission/assembly and cell adhesion typical of AD in the APP23 brain. Comparative proteomics were in line with these observations as it also revealed association of proteins of both pathways to be linked to TG2 in APP23 brains Together, our data showed that TG2 deletion led to considerable network alterations consistent with a role of TG2 in (dys)regulation of synaptic transmission and cell adhesion in APP23 brains.