{"doi":"10.1101/2022.01.07.475414","title":"Free diffusion of PI(4,5)P <sub>2</sub> in the plasma membrane in the presence of high density effector protein complexes","abstract":"Abstract The lipid phosphatidyl-D- myo- inositol-4,5- bis phosphate [PI(4,5)P 2 ] is a master regulator of plasma membrane (PM) function. It engages effector proteins that regulate diverse traffic, transport, signaling and cytoskeletal processes that define PM structure and function. How a single class of lipid molecules independently regulate so many parallel processes remains an open question. We tested the hypothesis that spatially segregated pools of PI(4,5)P 2 are associated with, and thus reserved for regulation of, different functional complexes in the PM. The mobility of PI(4,5)P 2 in the membrane was measured using lipid biosensors by single particle tracking photoactivation localization microscopy (sptPALM). We found that PI(4,5)P 2 , and several other classes of inner PM lipids, diffuse rapidly at approximately 0.3 µm 2 /s with largely Brownian motion, although they spend approximately a third of their time diffusing much more slowly. Surprisingly, areas of the PM occupied by PI(4,5)P 2 -dependent complexes, such endoplasmic-reticulum:PM contact sites, clathrin-coated structures, and several actin cytoskeletal elements including focal adhesions, did not cause a change in PI(4,5)P 2 lateral mobility. Only the spectrin and septin cytoskeletons were observed to produce a slowing of PI(4,5)P 2 diffusion. We conclude that even structures with high densities of PI(4,5)P 2 -engaging effector proteins, such as clathrin coated pits and focal adhesions, do not corral free PI(4,5)P 2 , questioning a role for spatially segregated PI(4,5)P 2 pools in organizing and regulating parallel PM functions.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2022,"id":302511,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9551,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":870273,"name":"Anna C. Cassidy","orcid":"0000-0002-5171-9002","position":1,"is_corresponding":false},{"id":278210,"name":"James P. Zewe","orcid":"0000-0001-5086-9052","position":2,"is_corresponding":false},{"id":278212,"name":"Rachel C. Wills","orcid":"0000-0003-2161-9235","position":3,"is_corresponding":false},{"id":245412,"name":"Gerald Hammond","orcid":"0000-0002-6660-3272","position":4,"is_corresponding":false},{"id":418055,"name":"Jonathan Pacheco","orcid":"0000-0001-6880-5874","position":0,"is_corresponding":true}],"reference_count":70,"raw_metadata":null,"created_at":"2026-07-19T00:32:16.279991Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}