Let's make a short break down

A brief breakdown of the most important aspects of how to look inside a cell

Transcription Factors and Signal Transduction

Just how complicated a single eukaryotic cell is becomes clear if you simply look at individual aspects that are somehow the same in every single cell, whether specific intestinal endothelium, lung endothelium or stellate macrophages, and yet fulfill specific and completely different functions. Moreover, they are absolutely context-specific.

I'll try to break down the most important intracellular factors that make intracellular understanding so complicated and that make you realize that you are dealing with "intelligent" design and that life is already starting here (without adaptive immune cells with TLRs) for an overview (I think that I will "modify" and supplement them again from time to time):

receptor shaping

Cell signaling: triggered by receptors. Trigger every conceivable form of reaction and are strongly dependent on the cell membrane, the receptor sharpening (i.e. the intensity of the de(?re?)-formation of the receptor). They generally occur as signaling cascades (i.e. downstream towards nuclear factors and transcription factors) and are ALWAYS in an unmanageable protein-protein interaction network with other signaling cascades. (See great work: Transcription factors: Bridge between cell signaling and gene regulation)

signaling via ATPase (most signals are using Phosphorylation. e.g. one of the hugest families, the Mitogen Activated Protein Kinases): Mitogen-activated protein kinases activate the serine/threonine kinases Mnk1 and Mnk2)

Transcription factors: Translate the interaction of cell signaling by targeting genes on DNA in converting and/or transcribing genes (see "beginner-friendly"™ read Regulation of gene expression by transcription factoracetylation & Transcription factors and evolution: An integral part of gene expression (Review) ) Very complicated interactions because of crosstalks with e.g. BRCA1/2 and P53 (see Systems Biology-Based Identification of Crosstalk between E2F Transcription Factors and the Fanconi Anemia Pathway)

E2F as an example

Eukaryotic initiation factors: Regulate ribosomal activation and translation (see The eukaryotic translation initiation factors eIF1 and eIF1A induce an open conformation of the 40S ribosome & Eukaryotic Initiation Factor

example eiF2a

Ribosome should be clear? Translation of RNA and recruitment of tRNA (transferRNA) (see Quantitative analysis of tRNA abundance and modifications by nanopore RNA sequencing)

Ribosome and tRNA

siRNA, miRNA, lncRNA,(snoRNA) and probably a few I just forgot): are narrow non-coding RNA fragments that, among other things, regulate mRNA translation (read speed, expression rate, etc (see Mechanisms of miRNA-Mediated Gene Regulation from Common Downregulation to mRNA-Specific Upregulation & microRNAs slow translating ribosomes to prevent protein misfolding in eukaryotes & The snoRNA box C/D motif directs nucleolar targeting and also couples snoRNA synthesis and localization)

miRNA in gene silencing

And of course the immune system must not be missing. Cytosolic pattern recognition receptors (PRRs): Are the first line of the immune response, as they are part of the native immune system and can be found in every conceivable cell. Examples: RIG1, AIM2, and NLR(P3 best known). (Super complicated, see for example Intracellular innate immune receptors: Life inside the cell and they influence all the processes mentioned above and are in permanent crosstalk with them, sometimes use the same signaling cascades and make general understanding twice and three times more difficult).

NLRP3

And here's the joke, if you also want to think about TLRs: The Toll-Like receptors (part of the PRRs) are known to be found both intracellular (on the endosomes) and membrane-bound (anchored). Normally found on the immune cells. But hey ho: It gets tricky when you realize that they are not only found there: Vascular endothelial cell Toll-like receptor pathways in sepsis, because vascular endothelial cells also express TLRs.

TLR activation