Polymerizes chitin, a structural polymer of the cell wall and septum, by transferring the sugar moiety of UDP-GlcNAc to the non-reducing end of the growing chitin polymer (PubMed:16278457). Activated by CSR2, it produces chitin that is deacetyled to chitosan, which is required to maintain cell wall integrity (PubMed:16278457, PubMed:16102007, PubMed:17400891, PubMed:32743128). Conversion of chitin to chitosan offers an advantage during infection, as chitosan is less readily detected by host immunosurveillance mechanisms (PubMed:32071275). [(1->4)-N-acetyl-beta-D-glucosaminyl](n) + UDP-N-acetyl-alpha-D-glucosamine = [(1->4)-N-acetyl-beta-D-glucosaminyl](n+1) + H(+) + UDP Palmitoylated by PFA4; required for proper subcellular localization. Increases cellular chitin level and decreases cellular chitosan level (PubMed:16278457, PubMed:17400891, PubMed:32071275). Swollen cell with abnormal cytokinesis (PubMed:16278457, PubMed:17400891, PubMed:32743128, PubMed:32071275). Abnormal capsular morphology: lower fiber density, short fibers, decreases capsular diameter (PubMed:32743128). Decreases extracellular vesicle secretion (PubMed:32743128). Melanization of surrounding media (PubMed:16278457, PubMed:17400891). Increases CHS5 and CHS7 RNA level (PubMed:16278457). Sensitive to: caspofungin (cell wall stress inducer), sodium dodecyl sulfate (cell wall stress inducer), Congo Red (cell wall stress inducer), Calcofluor White (cell wall stressor), caffeine, NaCl (osmotic stressor), high temperature (PubMed:16278457, PubMed:17400891, PubMed:31266771, PubMed:32071275). Intranasal inoculation with high inoculum causes rapid mortality in mouse; mortality is not due to fungal burden but to a strong hyperinflammatory response in the host driven by host neutrophils (PubMed:32071275). Belongs to the chitin synthase family. Class IV subfamily.