The function of IFT140 (intraflagellar transport 140, ENSG00000187535) is as follows. Component of the IFT complex A (IFT-A), a complex required for retrograde ciliary transport and entry into cilia of G protein- coupled receptors (GPCRs) (PubMed:20889716, PubMed:22503633, PubMed:36775821). Plays a pivotal role in proper development and function of ciliated cells through its role in ciliogenesis and/or cilium maintenance (PubMed:22503633). Required for the development and maintenance of the outer segments of rod and cone photoreceptor cells. Plays a role in maintenance and the delivery of opsin to the outer segment of photoreceptor cells (By similarity). {ECO:0000250|UniProtKB:E9PY46, ECO:0000269|PubMed:20889716, ECO:0000269|PubMed:22503633, ECO:0000269|PubMed:28724397, ECO:0000269|PubMed:36775821}.